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2023-10-18
Chiral spin textures creation and dynamics in a rectangular nanostructure
Controlled creation of stable chiral spin textures is required to use them as an energy-efficient information carrier in spintronics. Here we have studied the stable creation of isolated chiral spin texture (skyrmion and antiskyrmion) and its pair through the magnetization reversal of a rectangular nanostructure using ...
2310.12129v1
2023-12-21
Generation of femtosecond spin-polarized current pulses at Fe/MgO interface by quasi-static voltage
The generation of short spin-current pulses is essential for fast spintronic devices. So far, spin current pulses are generated by femtosecond laser pulses which drive spins from a ferromagnetic metal layer. However, the need for miniaturization, simplicity and energy efficiency favour electric-field control of spintro...
2312.13698v1
2023-12-29
Quantum-grade nanodiamonds for ultrabright spin detection in live cells
Optically accessible spin-active nanomaterials are promising as quantum nanosensors for probing biological samples. However, achieving bioimaging-level brightness and high-quality spin properties for these materials is challenging and hinders their application in quantum biosensing. Here, we demonstrate ultrabright flu...
2312.17603v2
2024-01-10
Narrowly avoided spin-nematic phase in BaCdVO(PO$_4$)$_2$: NMR evidence
We present a $^{31}$P nuclear magnetic resonance (NMR) investigation of BaCdVO(PO$_4$)$_2$ focusing on the nearly saturated regime between $\mu_0H_{c1}$ = 4.05 T and $\mu_0H_{c2}$ = 6.5 T, used to be considered as a promising candidate for a spin-nematic phase. NMR spectra establish the absence of any dipolar order the...
2401.05269v1
2024-03-04
Multidimensional spectroscopy of nuclear spin clusters in diamond
Optically active spin defects in solids offer promising platforms to investigate nuclear spin clusters with high sensitivity and atomic-site resolution. To leverage near-surface defects for molecular structure analysis in chemical and biological contexts using nuclear magnetic resonance (NMR), further advances in spect...
2403.02114v1
2024-03-21
Realizing topological quantum magnets with atomic spins on surfaces
Artificial quantum systems have emerged as indispensable platforms to realize exotic topological matter in a well-controlled manner. Here, we demonstrate topological quantum Heisenberg spin lattices, engineered with spin chains and two-dimensional spin arrays using spin 1/2 atoms on insulating films in a scanning tunne...
2403.14145v1
2024-03-26
Nuclear spin-spin interactions in CdTe probed by zero and ultra-low-field optically detected NMR
Nuclear magnetic resonance (NMR) is particularly relevant for studies of internuclear spin coupling at zero and ultra-low fields (ZULF), where spin-spin interactions dominate over Zeeman ones. Here we report on ZULF NMR in CdTe. In this semiconductor all magnetic isotopes have spin $I = 1/2$, so that internuclear inter...
2403.17593v1
2024-04-11
Dynamical Reorientation of Spin Multipoles in Silicon Carbide by Transverse Magnetic Fields
The long-lived and optically addressable high-spin state of the negatively charged silicon vacancy ($\mathrm{V_{Si}}$) in silicon carbide makes it a promising system for applications in quantum technologies. Most studies of its spin dynamics have been performed in external magnetic fields applied along the symmetry axi...
2404.07915v1
2020-03-14
Enhanced longevity of the spin helix in low-symmetry quantum wells
In a semiconductor, collective excitations of spin textures usually decay rather fast due to D'yakonov-Perel' spin relaxation. The latter arises from spin-orbit coupling, which induces wave-vector-dependent spin rotations that, in conjunction with random disorder scattering, generate spin decoherence. However, symmetri...
2003.06544v2
2020-01-17
Thermal spin transport and spin in thermoelectrics
This article reviews the principles that govern the combined transport of spin, heat, and charge. The extensive thermodynamic quantity associated with spin transport is the magnetization; its Onsager-conjugate force is in general the derivative of the free energy with respect to the magnetization. Spins are carried in ...
2001.06366v1
1996-07-11
Exact results for resonating valence bonds states on 2D (narrow) systems
It is shown that the problem of calculating spin-spin correlation functions, in the dimers RVB states, on a possibly diluted 2D square lattice, can be formulated in terms of a transfer matrix. The transfer matrix is used for exact numerical calculations of spin-spin correlation functions on ladders up to four units wid...
9607076v2
1997-10-29
Relaxation Regimes of Spin Maser
Spin relaxation in a microscopic model of spin maser is studied theoretically. Seven qualitatively different regimes are found: free induction, collective induction, free relaxation, collective relaxation, weak superradiance, pure superradiance, and triggered superradiance. The initiation of relaxation can be originate...
9710311v1
1999-05-18
Spin-orbit scattering in d-wave superconductors
When non-magnetic impurities are introduced in a d-wave superconductor, both thermodynamic and spectral properties are strongly affected if the impurity potential is close to the strong resonance limit. In addition to the scalar impurity potential, the charge carriers are also spin-orbit coupled to the impurities. Here...
9905262v1
2000-01-10
SIN and SIS tunneling in cuprates
We calculate the SIN and SIS tunneling conductances for the spin-fermion model. We argue that at strong spin-fermion coupling, relevant to cuprates, both conductances have dip features near the threshold frequencies when a tunneling electron begin emitting propagating spin excitation. We argue that the resonance spin f...
0001125v1
2000-09-21
Dynamics of spin correlations in the spin-1/2 isotropic XY chain in a transverse field
Dynamic xx spin pair correlation functions for the isotropic spin-1/2 XY chain are calculated numerically for long open chains in the presence of a transverse magnetic field at finite temperature. As an application we discuss the temperature dependence of the spin-spin relaxation time in PrCl_3.
0009334v1
2000-10-10
Optical manipulation of nuclear spin by a two-dimensional electron gas
Conduction electrons are used to optically polarize, detect and manipulate nuclear spin in a (110) GaAs quantum well. Using optical Larmor magnetometry, we find that nuclear spin can be polarized along or against the applied magnetic field, depending on field polarity and tilting of the sample with respect to the optic...
0010139v1
2001-07-10
Spin Dynamics near the Superconductor-to-Insulator Transition in Impurity-Doped YBa2Cu4O8
We studied low-frequency spin dynamics near the impurity-induced superconductor-to-insulator transition for underdoped high-Tc superconductor YBa2(Cu1-xMx)4O8 (M=Ni, Zn) using the Cu nuclear quadrupole resonance (NQR) spin-echo technique. We observed remarkable suppression of the normal-state pseudo spin-gap and a loss...
0107187v1
2002-10-02
Local Magnetic Susceptibility of the Positive Muon in the Quasi 1D S=1/2 Antiferromagnet KCuF$_3$
We report muon spin rotation measurements of the local magnetic susceptibility around a positive muon in the paramagnetic state of the quasi one-dimensional spin 1/2 antiferromagnet KCuF$_3$. Signals from two distinct sites are resolved which have a temperature dependent frequency shift which is different than the magn...
0210060v1
2002-11-13
Test for Pairing Symmetry Based on Spin Fluctuations in Organic Superconductors $κ$-(BEDT-TTF)$_{2}$X
We propose that the superconducting pairing symmetry of organic superconductors $\kappa$-(BEDT-TTF)$_{2}$X can be determined by measuring the position in momentum space of the incommensurate peaks of the spin susceptibility. We show that the positions of these peaks are uniquely determined by the symmetry of the superc...
0211256v1
2003-02-17
Theory of spin density profile in the magnetization plateaus of SrCu_2(BO_3)_2
The two-dimensional spin-gap system ${\rm SrCu_2(BO_3)_2}$ shows unique physical properties due to the low-dimensionality character and the strong quantum fluctuations. Experimentally, 1/8-, 1/4-, and 1/3-plateaus have been observed in the magnetization curve under magnetic fields up to 70 Tesla, and the 1/2-plateau is...
0302332v1
2003-03-01
Electron Spin-Relaxation Times of Phosphorus Donors in Silicon
Pulsed electron paramagnetic resonance measurements of donor electron spins in natural phosphorus-doped silicon (Si:P) and isotopically-purified 28Si:P show a strongly temperature-dependent longitudinal relaxation time, T1, due to an Orbach process with DeltaE = 126 K. The 2-pulse echo decay is exponential in 28Si:P, w...
0303006v1
2003-05-23
A realization of Yangian and its applications to the bi-spin system
Yangian $Y(sl(2))$ is realized in the bi-spin system coupled with a time-dependent external magnetic field. It is shown that $Y(sl(2))$ generators can describe the transitions between the ``spin triplet'' and the ``spin singlet'' that evolve with time. Furthermore, new transition operators between the states with Berry...
0305550v1
2004-02-10
Spin-lattice NMR relaxation by anomalous translational diffusion
A model-free theoretical framework for a phenomenological description of spin-lattice relaxation by anomalous translational diffusion in inhomogeneous systems based on the fractional diffusion equation is developed. The dependence of the spin-lattice relaxation time on the size of the pores in porous glass Vycor is exp...
0402274v2
2004-02-12
Impurity-induced tuning of quantum well states in spin-dependent resonant tunneling
We report exact model calculations of the spin-dependent tunneling in double magnetic tunnel junctions in the presence of impurities in the well. We show that the impurity can tune selectively the spin channels giving rise to a wide variety of interesting and novel transport phenomena. The tunneling magnetoresistance, ...
0402324v1
2004-04-21
Spin state readout by quantum jump technique: for the purpose of quantum computing
Utilizing the Pauli-blocking mechanism we show that shining circular polarized light on a singly-charged quantum dot induces spin dependent fluorescence. Employing the quantum-jump technique we demonstrate that this resonance luminescence, due to a spin dependent optical excitation, serves as an excellent readout mecha...
0404494v1
2004-04-24
Spin and Charge Pumping by Ferromagnetic-Superconductor Order Parameters
We study transport in ferromagnetic-superconductor/normal-metal systems. It is shown that charge and spin currents are pumped from ferromagnetic superconductors into adjacent normal metals by adiabatic changes in the order parameters induced by external electromagnetic fields. Spin and charge pumping identify the symme...
0404591v2
2004-04-26
Spin filtering through a double-bend structure
We propose a simple scheme for the spin filter by studying the coherent transport of electrons through a double-bend structure in a quantum wire with a weak lateral magnetic potential which is much weaker than the Fermi energy of the leads. {\em Extremely large} spin polarized current in the order of {\em micro-Ampere}...
0404605v1
2005-01-03
Electron Spin-Lattice Relaxation of doped Yb3+ ions in YBa2Cu3Ox
The electron spin-lattice relaxation (SLR) times T1 of Yb3+‡ ions were measured from the temperature dependence of electron spin resonance linewidth in Y0.99Yb0.01Ba2Cu3Ox with different oxygen contents. Raman relaxation processes dominate the electron SLR. Derived from the temperature dependence of the SLR rate, ...
0501017v1
2005-11-28
Spin susceptibility of underdoped cuprates: the case of Ortho-II YBa_2Cu_3O_{6.5}
Recent inelastic neutron scattering measurements found that the spin susceptibility of detwinned and highly ordered ortho-II YBa_2Cu_3O_{6.5} exhibits, in both the normal and superconducting states, one-dimensional incommensurate modulations at low energies which were interpreted as a signature of dynamic stripes. We p...
0511661v1
2006-01-13
Spin tunneling through an indirect barrier
Spin-dependent tunneling through an indirect bandgap barrier like the GaAs/AlAs/GaAs heterostructure along [001] direction is studied by the tight-binding method. The tunneling is characterized by the proportionality of the Dresselhaus Hamiltonians at $\Gamma $ and $X$ points in the barrier and by Fano resonances. The ...
0601297v1
2006-03-27
Visualizing high-temperature spin dynamics in La1-xCaxMnO3 from a mapping of EPR linewidth and g factor
This paper presents an analysis of electron paramagnetic resonance parameters, i.e., g factor, linewidth, and intensity on powder samples of La1-xCaxMnO3 at the commensurate carrier concentrations of x = N/8 (N = 1, 2, 3, 4, 5, 6, and 7). We demonstrate that the mapping of EPR parameters offers a powerful tool to inves...
0603705v2
2006-09-13
Nonlinear Rashba Model and Spin Relaxation in Quantum Wells
We find that the Rashba spin splitting is intrinsically a nonlinear function of the momentum, and the linear Rasha model may overestimate it significantly, especially in narrow-gap materials. A nonlinear Rashba model is proposed, which is in good agreement with the numerical results from the eight-band kp theory. Using...
0609311v1
2006-10-01
Odd-frequency pairing and Josephson effect at superconducting interfaces
We demonstrate that, quite generally, the spin-singlet even-parity (spin-triplet odd-parity) pair potential in a superconductor induces the odd-frequency pairing component with spin-singlet odd-parity (spin-triplet even-parity) near interfaces. The magnitude of the induced odd-frequency component is enhanced in the pre...
0610017v3
2007-02-09
Spin-dependent transport properties in GaMnAs-based spin hot-carrier transistors
We have investigated the spin-dependent transport properties of GaMnAs-based three-terminal semiconductor spin hot-carrier transistor (SSHCT) structures. The emitter-base bias voltage VEB dependence of the collector current IC, emitter current IE, and base current IB shows that the current transfer ratio alpha (= IC / ...
0702239v1
2003-06-27
New effects in neutrino oscillations in matter and electromagnetic fields
Within the recently developed Lorentz invariant approach to neutrino spin and flavour oscillations the following four new effects are discussed: 1) neutrino spin oscillations in different electromagnetic field configurations, 2) neutrino spin precession and oscillations stimulated by weak interaction with background ma...
0306280v1
2001-05-25
Spin-vibrational 1+ states in 140Ce
The properties of collective I^$\Pi$=1+ states in double even semimagic nucleus 140Ce are investigated in random phase approximation(RPA). The calculation of the B(M1) strength, elastic gamma-scattering cross section $\sigma_(gamma)(\omega)$ and gamma-decay width $\Sigma_(gamma)(\omega_i)$ show that in 140Ce the isovec...
0105065v1
2003-06-18
Generation of Superposition Spin States in an Atomic Ensemble
A method for generating a mesoscopic superposition state of the collective spin variable of a gas of atoms is proposed. The state consists of a superposition of the atomic spins pointing in two slightly different directions. It is obtained by using off resonant light to carry out Quantum Non Demolition Measurements of ...
0306121v1
2005-09-18
The ultra-sensitive electrical detection of spin Rabi oscillation at paramagnetic defects
A short review of the pulsed electrically detected magnetic resonance (pEDMR) experiment is presented. PEDMR allows the highly sensitive observation of coherent electron spin motion of charge carriers and defects in semiconductors by means of transient current measurements. The theoretical foundations, the experimental...
0509120v1
2005-12-12
Fast polarimetry system for the application to spin quantum non-demolition measurement
We report the development of a fast pulse polarimeter for the application to quantum non-demolition measurement of atomic spin (Spin QND). The developed system was tunable to the atomic resonance of ytterbium atom and has narrow laser linewidth suitable for spin QND. Using the developed polarimeter, we successfully dem...
0512089v2
2007-07-13
Multiphoton antiresonance in large-spin systems
We study nonlinear response of a spin $S>1/2$ with easy-axis anisotropy. The response displays sharp dips or peaks when the modulation frequency is adiabatically swept through multiphoton resonance. The effect is a consequence of a special symmetry of the spin dynamics in a magnetic field for the anisotropy energy $\pr...
0707.2107v1
2007-07-27
Leakage-induced decoherence during single electron spin manipulation in a double quantum dot
Coherent single electron spin oscillation in a double quantum dot system driven by a magnetic electron spin resonance field is studied theoretically using a Bloch-type rate equation approach. The oscillation frequency and relaxation time obtained using typical model parameters are consistent with experiment findings. T...
0707.4040v1
2007-10-06
Spin Anisotropy in ZnCu_3(OH)_6Cl_2
The spin anisotropic exchange interaction is suggested to contribute significantly to the abnormal upturn of the magnetic susceptibility in the ZnCu$_3$(OH)$_6$Cl$_2$. The saturation of the magnetic susceptibility below 300 mK observed in the muon spin resonance ($\mu$SR) experiment is the quantum effect of the spin fl...
0710.1334v3
2007-11-26
Kondo Resonance in the Presence of Spin-Polarized Currents
We propose an improved method of the equation of motion approach to study the Kondo problem in spin-dependent non-equilibrium conditions. We find that the previously introduced additional renormalization for non-equilibrium Kondo effects is not required when we use a proper decoupling scheme. Our improved formulation i...
0711.4121v1
2008-01-18
Selective Spin Injection Controlled by Electrical way in Ferromagnet/Quantum Dot/Semiconductor system
Selective and large polarization of current injected into semiconductor (SC) is predicted in Ferromagnet (FM)/Quantum Dot (QD)/SC system by varying the gate voltage above the Kondo temperature. In addition, spin-dependent Kondo effect is also revealed below Kondo temperature. It is found that Kondo resonances for up sp...
0801.2922v1
2008-01-30
Enhanced thermal stability and spin-lattice relaxation rate of N@C60 inside carbon nanotubes
We studied the temperature stability of the endohedral fullerene molecule, N@C60, inside single-wall carbon nanotubes using electron spin resonance spectroscopy. We found that the nitrogen escapes at higher temperatures in the encapsulated material as compared to its pristine, crystalline form. The temperature dependen...
0801.4783v1
2008-07-15
Dynamics of dissipative coupled spins: decoherence and relaxation
We study the reduced dynamics of interacting spins, each coupled to its own bath of bosons. We derive the solution in analytic form in the white-noise limit and analyze the rich behaviors in diverse limits ranging from weak coupling and/or low temperature to strong coupling and/or high temperature. We also view the one...
0807.2342v1
2008-10-24
Polarization and entanglement in spin systems
We established important relationships between entanglement measures and the order parameter (spin polarization) in nuclear spin systems controlled by the nuclear magnetic resonance (NMR) technique. Since spin polarization can be easily manipulated by the NMR technique, experimentalists are presented with an opportunit...
0810.4388v1
2008-11-25
Theory of electric field induced one-magnon resonance in cycloidal spin magnets
We propose a new mechanism to induce a novel one-magnon excitation by the electric component of light in cycloidal spin states, i.e. so called electromagnon process. We calculated optical spectra in the cycloidal spin structures as observed in multiferroic perovskite manganites RMnO3 where novel magnetic excitations in...
0811.4082v1
2009-03-13
Spin-Exchange-Relaxation-Free Magnetometry Using Elliptically-Polarized Light
Spin-exchange relaxation free alkali-metal magnetometers typically operate in the regime of high optical density, presenting challenges for simple and efficient optical pumping and detection. We describe a high-sensitivity Rb magnetometer using a single elliptically-polarized off-resonant laser beam. Circular component...
0903.2447v1
2009-04-22
Current-induced nuclear-spin activation in a two-dimensional electron gas
Electrically detected nuclear magnetic resonance was studied in detail in a two-dimensional electron gas as a function of current bias and temperature. We show that applying a relatively modest dc-current bias, I_dc ~ 0.5 microAmps, can induce a re-entrant and even enhanced nuclear spin signal compared with the signal ...
0904.3405v1
2009-05-08
Hyperfine tensors of nitrogen-vacancy center in diamond from \emph{ab initio} calculations
We determine and analyze the charge and spin density distributions of nitrogen-vacancy (N-V) center in diamond for both the ground and excited states by \emph{ab initio} supercell calculations. We show that the hyperfine tensor of $^{15}$N nuclear spin is negative and strongly anisotropic in the excited state, in contr...
0905.1169v1
2009-06-04
Quark-Hadron Duality in Neutron Spin-Structure and g_2 moments at intermediate Q**2
Jefferson Lab experiment E01-012 measured the He-3 spin-structure functions and virtual photon asymmetries in the resonance region in the momentum transfer range 1.0<Q**2<4.0(GeV/c)**2. Our data, when compared with existing deep inelastic scattering data, were used to test quark-hadron duality in g_1 and A_1 for He-3 a...
0906.0928v1
2009-09-15
The effective spin concept to analyze coherent charge transport in mesoscopic systems
An effective spin concept is introduced to examine the mathematical and physical analogy between phase coherent charge transport in mesoscopic systems and quantum operations on spin based qubits. When coupled with the Bloch sphere concept, this isomorphism allows formulation of transport problems in a language more fam...
0909.2892v1
2010-04-01
Phenomenological Model of Longitudinal Spin Fluctuations in Itinerant Antiferromagnets
We present the phenomenological analysis of the spectrum of longitudinal spin fluctuations in isotropic itinerant electron antiferromagnets with account of spin anharmonicity giving rise to coupling of transverse and longitudinal normal modes. The spectrum consists of a quasielastic part forming a central peak or a dip...
1004.0136v1
2010-05-17
QND Measurement of Large-Spin Ensembles by Dynamical Decoupling
Quantum non-demolition (QND) measurement of collective variables by off-resonant optical probing has the ability to create entanglement and squeezing in atomic ensembles. Until now, this technique has been applied to real or effective spin one-half systems. We show theoretically that the build-up of Raman coherence pre...
1005.2807v1
2010-06-28
Eliashberg Analysis of Optical Spectra Reveals Strong Coupling of Charge Carriers to Spin Fluctuations in Superconducting Iron Pnictides
The temperature and frequency dependences of the optical conductivity of Co and Ni-doped BaFe2As2 are analyzed and the electron-boson spectral density a2F(w) extracted using Eliashberg's formalism. The characteristic energy of a large peak in the spectrum around 10 meV coincide with the resonance peak in the spin excit...
1006.5468v1
2011-04-28
Spin and Orbital Characters of Excitations in Iron Arsenide Superconductors Revealed by Simulated Fe L-Edge RIXS
We theoretically examine the orbital excitations coupled to the spin degree of freedom in the parent state of the iron-arsenide superconductor, based on the calculation in a five-band itinerant model. The calculated Fe $L_3$-edge resonant inelastic x-ray scattering (RIXS) spectra disclose the presence of spin-flip exci...
1104.5424v2
2011-07-04
Minimization of the Switching Time of a Synthetic Free Layer in Thermally Assisted Spin Torque Switching
We theoretically studied the thermally assisted spin torque switching of a synthetic free layer and showed that the switching time is minimized if the condition H_J=|H_s|/(2 alpha) is satisfied, where H_J, H_s and alpha are the coupling field of two ferromagnetic layers, the amplitude of the spin torque, and the Gilber...
1107.0753v2
2011-07-14
Coherent control of two nuclear spins using the anisotropic hyperfine interaction
We demonstrate coherent control of two nuclear spins mediated by the magnetic resonance of a hyperfine-coupled electron spin. This control is used to create a double nuclear coherence in one of the two electron spin manifolds, starting from an initial thermal state, in direct analogy to the creation of an entangled (Be...
1107.2884v2
2011-08-09
Evidence for spin memory in the electron phase coherence in graphene
We measure the dependence of the conductivity of graphene as a function of magnetic field, temperature and carrier density and discover a saturation of the dephasing length at low temperatures that we ascribe to spin memory effects. Values of the spin coherence length up to eight microns are found to scale with the mea...
1108.2067v1
2011-09-19
Storage and Retrieval of a Microwave Field in a Spin Ensemble
We report the storage and retrieval of a small microwave field from a superconducting resonator into collective excitations of a spin ensemble. The spins are nitrogen-vacancy centers in a diamond crystal. The storage time of the order of 30 ns is limited by inhomogeneous broadening of the spin ensemble.
1109.3960v1
2011-09-22
Probing the spin states of three interacting electrons in quantum dots
We observe a low-lying sharp spin mode of three interacting electrons in an array of nanofabricated AlGaAs/GaAs quantum dots by means of resonant inelastic light scattering. The finding is enabled by a suppression of the inhomogeneous contribution to the excitation spectra obtained by reducing the number of optically-p...
1109.4758v1
2011-10-24
Spin-orbital Kondo effect in a parallel double quantum dot
Transport properties of the two-orbital Kondo effect involving both spin and orbital (pseudospin) degrees of freedom were examined in a parallel double quantum dot with a sufficient interdot Coulomb interaction and negligibly small interdot tunneling. The Kondo effect was observed at the interdot Coulomb blockade regio...
1110.5130v1
2012-06-15
Optical control of the spin state of two Mn atoms in a quantum dot
We report on the optical spectroscopy of the spin of two magnetic atoms (Mn) embedded in an individual quantum dot interacting with either a single electron, a single exciton and single trion. As a result of their interaction to a common entity, the Mn spins become correlated. The dynamics of this process is probed by ...
1206.3491v1
2012-10-18
Enhanced Inverse Spin-Hall Effect in Ultrathin Ferromagnetic/Normal Metal Bilayers
We measure electrically detected ferromagnetic resonance in microdevices patterned from ultra-thin Co/Pt bilayers. Spin pumping and rectification voltages are observed and distinguished via their angular dependence. The spin-pumping voltage shows an unexpected increase as the cobalt thickness is reduced below 2 nm. Thi...
1210.5230v1
2012-11-12
Spin polarization and magnetoresistance through a ferromagnetic barrier in bilayer graphene
We study spin dependent transport through a magnetic bilayer graphene nanojunction configured as two dimensional normal/ferromagnetic/normal structure where the gate-voltage is applied on the layers of ferromagnetic graphene. Based on the fourband Hamiltonian, conductance is calculated by using Landauer Butikker formul...
1211.2701v1
2012-11-29
Pumping $ac$ Josephson current in the Single Molecular Magnets by spin nutation
We demonstrate that an {\it ac} Josephson current is pumped through the Single Molecular Magnets (SMM) by the spin nutation. The spin nutation is generated by applying a time dependent magnetic field to the SMM. We obtain the flowing charge current through the junction by working in the tunneling limit and employing Gr...
1211.6879v1
2012-12-18
Spin system trajectory analysis under optimal control pulses
Several methods are proposed for the analysis, visualization and interpretation of high-dimensional spin system trajectories produced by quantum mechanical simulations. It is noted that expectation values of specific observables in large spin systems often feature fast, complicated and hard-to-interpret time dynamics a...
1212.4454v1
2013-06-18
Ultrasensitive Detection of Majorana Fermions via Spin-based Optomechanics with Carbon Nanotubes
We propose a novel optical method to detect the existence of Majorana fermions at the ends of the semiconductor nanowire via the coupling to an electron spin trapped on a carbon nanotube resonator under the control of a strong pump field and a weak probe field. The coupling strength of Majorana fermion to the spin in t...
1306.4102v1
2014-02-13
Inhomogeneous slowing down of spin fluctuations induced by charge stripe order in 1/8-doped lanthanum cuprates
We report $^{139}$La nuclear magnetic resonance (NMR) measurements on La$_{2-x}$Sr$_x$CuO$_4$ ($0.07\leq x \leq 0.15$) and La$_{2-x}$Ba$_x$CuO$_4$ ($x=1/8$) single crystals, focusing on the spin freezing observed in 1/8-doped lanthanum cuprates. Charge stripe order seems to induce the inhomogeneous slowing down of spin...
1402.3077v3
2014-03-18
31P NMR Investigation of the Superconductor LiFeP (Tc = 5 K)
We investigate the static and dynamic spin susceptibility of the 111 type Fe-based superconductor LiFeP with Tc ~ 5 K through the measurement of Knight shift 31K and the spin-lattice relaxation rate 1/T1 at 31P site by nuclear magnetic resonance. The constant 31K, small magnitudes of 1/T1T, along with the resistivity r...
1403.4458v1
2014-09-16
Sensitivity to small perturbations in systems of large quantum spins
We investigate the sensitivity of nonintegrable large-spin quantum lattices to small perturbations with a particular focus on the time reversal experiments known in statistical physics as "Loschmidt echoes" and in nuclear magnetic resonance (NMR) as "magic echoes". Our numerical simulations of quantum spin-$7\frac{1}{2...
1409.4763v1
2014-09-22
All optical control of a single electron spin in diamond
Precise coherent control of the individual electronic spins associated with atom-like impurities in the solid state is essential for applications in quantum information processing and quantum metrology. We demonstrate all-optical initialization, fast coherent manipulation, and readout of the electronic spin of the nega...
1409.6372v1
2015-02-24
Spin rectification for collinear and non-collinear magnetization and external magnetic field configurations
Spin rectification in a single crystal Fe/Au/Fe sandwich is electrically detected for collinear and non-collinear magnetization and external magnetic field configurations. The line shape, line width and signal polarity are analysed. The spin rectication theory has been much extended by taking the magneto-crystalline an...
1502.06859v1
2015-04-08
Electron spin polarization by isospin ordering in correlated two-layer quantum Hall systems
Enhancement of the electron spin polarization in a correlated two-layer two-dimensional electron system at a total Landau level filling factor of one is reported. Using resistively detected nuclear magnetic resonance, we demonstrate that the electron spin polarization of two closely-spaced two-dimensional electron syst...
1504.02007v1
2015-09-14
Spin measurement using cycling transitions of a two-electron quantum dot molecule
Two-electron charged self-assembled quantum dot molecules exhibit a decoherence-avoiding singlet-triplet qubit subspace and an efficient spin-photon interface. Here, we demonstrate that the cycling transitions originating from auxiliary ground states in the same system allow for an efficient optical read-out of a singl...
1509.04171v1
2018-06-21
Pulse sequences for controlled 2- and 3-qubit gates in a hybrid quantum register
We propose and demonstrate a quantum control scheme for hybrid quantum registers that can reduce the operation time, and therefore the effects of relaxation, compared to existing implementations. It combines resonant excitation pulses with periods of free precession under the internal Hamiltonian of the qubit system. W...
1806.08408v1
2018-09-07
Optimal Spin Squeezed Steady State induced by the dynamics of non-hermtian hamiltonians
In this work, we study the time evolution of a coherent spin state under the action of a non-hermitian hamiltonian. The hamiltonian is modeled by a one-axis twisting term plus a Lipkin-type interaction. We show that when the Lipkin interaction is switched on, depending on the relative values of the coupling constants, ...
1809.02683v1
2012-09-12
Coherent spin control by electrical manipulation of the magnetic anisotropy
High-spin paramagnetic manganese defects in polar piezoelectric zinc oxide exhibit a simple almost axial anisotropy and phase coherence times of the order of a millisecond at low temperatures. The anisotropy energy is tunable using an externally applied electric field. This can be used to control electrically the phase...
1209.2745v2
2012-09-19
Dynamical evolution of an inverted spin ensemble in a cavity: Inhomogeneous broadening as a stabilizing mechanism
We study the evolution of an inverted spin ensemble coupled to a cavity. The inversion itself presents an inherent instability of the system; however, the inhomogeneous broadening of spin-resonance frequencies presents a stabilizing mechanism, and a stability criterion is derived. The detailed behavior of mean values a...
1209.4167v1
2018-12-30
Entangling and squeezing atoms by weak measurement
A weak measurement approach is proposed to entangle and squeeze atoms. We show that even for very small coupling strength between light and atoms, one can achieve large squeezing unattainable with normal measurement-based squeezing. Post-selecting the photons interacting with spins via a weak off-resonant quantum nonde...
1812.11548v1
2017-02-24
Elucidation of the helical spin structure of FeAs
We present the results of resonant x-ray scattering measurements and electronic structure calculations on the monoarsenide FeAs. We elucidate details of the magnetic structure, showing the ratio of ellipticity of the spin helix is larger than previously thought, at 2.58(3), and reveal both a right-handed chirality and ...
1702.07660v1
2018-04-04
Independence of spin-orbit torques from the exchange bias direction in Ni$_{81}$Fe$_{19}$/IrMn bilayers
We investigated a possible correlation between spin Hall angles and exchange bias in Ni$_{81}$Fe$_{19}$/IrMn samples by performing spin torque ferromagnetic resonance measurements. This correlation is probed by patterning of Ni$_{81}$Fe$_{19}$/IrMn bilayers in different relative orientations with respect to the exchang...
1804.01612v1
2019-03-29
Adiabatic population transfer of dressed spin states with quantum optimal control
We report theoretical studies of adiabatic population transfer using dressed spin states. Quantum optimal control using the algorithm of Chopped Random Basis (CRAB) has been implemented in a negatively charged diamond nitrogen vacancy center that is coupled to a strong and resonant microwave field. We show that the dre...
1903.12651v1
2021-08-02
Trapping the carrier in the spin-locked MoS2 atomic valley by absorption of chiral L-cysteine
This work, demonstrate enhanced valley contrasting spin-momentum locked chiral states at van der Waal interface of chiral L-cysteine and mono-atomically thin MoS2 placed at Si/SiO2 substrate at ambient condition. Helicity dependent photoluminescence and resonance Raman measurement highlights spin-locked transitions for...
2108.01106v2
2008-06-24
Spin-vortex nucleation in a Bose-Einstein condensate by a spin-dependent rotating trap
A method to produce a spin-dependent rotating potential using near-resonant circularly polarized laser beams is proposed. It is shown that half-quantum vortices are nucleated in a spinor Bose-Einstein condensate with an antiferromagnetic interaction. In contrast to the vortex nucleation in a scalar BEC, the spin-vortex...
0806.3840v1
2019-01-29
Electron interferometry and quantum spin Hall phase in silicene
We discuss devices for detection of the topological insulator phase based on the two-path electron interference. For that purpose we consider buckled silicene for which a local energy gap can be opened by vertical electric field to close one of the paths and for which the quantum spin Hall insulator conditions are cont...
1901.10161v1
2021-01-20
Twisted light-induced spin-spin interaction in a chiral helimagnet
We theoretically investigate how the orbital angular momentum of light can affect a chiral magnetic order. Here, we consider a metallic chiral helimagnet, which is under stationary radiation of a resonant optical vortex beam. We propose a novel interaction between local spins considering microscopic interactions betwee...
2101.10131v2
2021-11-09
Parametric mechanism of magnetization reversal in FeCoB nanomagnet by a magnetic field of spin-accumulated electrons
Spin-polarized electrons are accumulated at nanomagnet boundaries due to the Spin Hall effect. The small magnetic field, which is induced by the spin accumulation, is able to reverse the nanomagnet magnetization when the conditions of parametric resonance are met. The features of this parametric mechanism of magnetizat...
2111.05438v1
2021-12-22
Observation of quantum phase-synchronization in a nuclear spin-system
We report an experimental study of phase-synchronization in a pair of interacting nuclear spins subjected to an external drive in nuclear magnetic resonance architecture. A weak transition-selective radio-frequency field applied on one of the spins is observed to cause phase-localization, which is experimentally establ...
2112.12088v2
2022-01-28
Theory of spin-excitation anisotropy in the nematic phase of FeSe obtained from RIXS measurements
Recent resonant inelastic x-ray scattering (RIXS) experiments have detected a significant high-energy spin-excitation anisotropy in the nematic phase of the enigmatic iron-based superconductor FeSe, whose origin remains controversial. We apply an itinerant model previously used to describe the spin-excitation anisotrop...
2201.12008v2
2022-07-15
Target normal single-spin asymmetry in inclusive electron-nucleon scattering with two-photon exchange: Analysis using $1/N_c$ expansion
We calculate the target normal single-spin asymmetry caused by two-photon exchange in inclusive electron-nucleon scattering in the resonance region. Our analysis uses the $1/N_c$ expansion of low-energy QCD and combines $N$ and $\Delta$ intermediate and final states using the contracted $SU(4)$ spin-flavor symmetry. Th...
2207.07588v1
2023-11-24
Plasmonically engineered nitrogen-vacancy spin readout
Ultra-precise readout of single nitrogen-vacancy (NV) spins hold promise for major advancements in quantum sensing and computing technologies. We predict significant brightness and contrast enhancements in NV spin qubit readout and optically detected magnetic resonance (ODMR) arising from plasmonic interaction. We pres...
2311.14266v1
1999-05-20
Spin dynamics simulation of the three-dimensional XY model: Structure factor and transport properties
We present extensive Monte-Carlo spin dynamics simulations of the classical XY model in three dimensions on a simple cubic lattice with periodic boundary conditions. A recently developed efficient integration algorithm for the equations of motion is used, which allows a substantial improvement of statistics and large i...
9905295v1
2000-12-01
Magnetic and orbital ordering in cuprates and manganites
The mechanisms of magnetic and orbital interactions due to double exchange (DE) and superexchange (SE) in transition metal oxides with degenerate e_g orbitals are presented. Specifically, we study the effective spin-orbital models derived for the d^9 ions as in KCuF_3, and for the d^4 ions as in LaMnO_3, for spins S=1/...
0012013v1
2005-08-08
Site dilution of quantum spins in the honeycomb lattice
We discuss the effect of site dilution on both the magnetization and the density of states of quantum spins in the honeycomb lattice, described by the antiferromagnetic Heisenberg spin-S model. For this purpose a real-space Bogoliubov-Valatin transformation is used. In this work we show that for the S>1/2 the system ca...
0508204v1
2007-02-01
Intensity of Brillouin light scattering from spin waves in magnetic multilayers with noncollinear spin configurations: Theory and experiment
The scattering of photons from spin waves (Brillouin light scattering -- BLS) is a well-established technique for the study of layered magnetic systems. The information about the magnetic state and properties of the sample is contained in the frequency position, width, and intensity of the BLS peaks. Previously [Phys. ...
0702021v1
2013-11-11
Three-dimensional light-matter interface for collective spin squeezing in atomic ensembles
We study the three-dimensional nature of the quantum interface between an ensemble of cold, trapped atomic spins and a paraxial laser beam, coupled through a dispersive interaction. To achieve strong entanglement between the collective atomic spin and the photons, one must match the spatial mode of the collective radia...
1311.2328v2
2018-03-23
Direct observation of incommensurate magnetism in Hubbard chains
The interplay between magnetism and doping is at the origin of exotic strongly correlated electronic phases and can lead to novel forms of magnetic ordering. One example is the emergence of incommensurate spin-density waves with a wave vector that does not match the reciprocal lattice. In one dimension this effect is a...
1803.08892v1
2020-11-09
Classical many-body chaos with and without quasiparticles
We study correlations, transport and chaos in a Heisenberg magnet as a classical model many-body system. By varying temperature and dimensionality, we can tune between settings with and without symmetry breaking and accompanying collective modes or quasiparticles. We analyse both conventional and out-of-time-ordered sp...
2011.04700v1