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1.
Magnetic proximity effect induced spin splitting in two-dimensional antimonene/Fe3GeTe2 van der Waals heterostructures 下载免费PDF全文
Recently, two-dimensional van der Waals (vdW) magnetic heterostructures have attracted intensive attention since they can show remarkable properties due to the magnetic proximity effect. In this work, the spin-polarized electronic structures of antimonene/Fe3GeTe2 vdW heterostructures were investigated through the first-principles calculations. Owing to the magnetic proximity effect, the spin splitting appears at the conduction-band minimum (CBM) and the valence-band maximum (VBM) of the antimonene. A low-energy effective Hamiltonian was proposed to depict the spin splitting. It was found that the spin splitting can be modulated by means of applying an external electric field, changing interlayer distance or changing stacking configuration. The spin splitting energy at the CBM monotonously increases as the external electric field changes from -5 V/nm to 5 V/nm, while the spin splitting energy at the VBM almost remains the same. Meanwhile, as the interlayer distance increases, the spin splitting energies at the CBM and VBM both decrease. The different stacking configurations can also induce different spin splitting energies at the CBM and VBM. Our work demonstrates that the spin splitting of antimonene in this heterostructure is not singly dependent on the nearest Sb—Fe distance, which indicates that magnetic proximity effect in heterostructures may be modulated by multiple factors, such as hybridization of electronic states and the local electronic environment. The results enrich the fundamental understanding of the magnetic proximity effect in two-dimensional vdW heterostructures. 相似文献
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J. Kossut 《Solid State Communications》1978,27(11):1237-1240
The electron density of states of a semiconductor in magnetic field exhibits an oscillatory behaviour. The amplitude of these oscillations is studied theoretically as a function of the electron spin splitting. The amplitude is shown to be strongly reduced when the spin splitting is equal to the half of the orbital splitting ?ω, provided that the collision broadening of the electronic levels is large enough. This fact should be reflected in a similar reduction of the amplitude of various quantum oscillatory phenomena, e.g. Shubnikov-de Haas effect. 相似文献
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I. I. Klimovskih M. V. Rusinova A. G. Rybkin A. A. Rybkina E. V. Zhizhin A. M. Shikin 《Bulletin of the Russian Academy of Sciences: Physics》2014,78(1):39-42
The electronic and spin structure of quantum-well and interface states, formed in the system, consisting of bilayer of Bi on 1 ML Ag/W(110) was investigated by angle- and spin- resolved photoelectron spectroscopy. It has been shown that interface states are formed in local surface-projected gap of W(110) and are characterized by spin polarization and spin-orbit splitting, corresponding to surface resonances with high density spin-polarized states near Fermi edge. 相似文献
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Yi-Ming Liu 《中国物理 B》2022,31(5):57201-057201
New characteristics of the Kondo effect, arising from spin chirality induced by the Berry phase in the equilibrium state, are investigated. The analysis is based on the hierarchical equations of motion (HEOM) approach in a triangular triple quantum-dot (TTQD) structure. In the absence of magnetic field, TTQD has four-fold degenerate chiral ground states with degenerate spin chirality. When a perpendicular magnetic field is applied, the chiral interaction is induced by the magnetic flux threading through TTQD and the four-fold degenerate states split into two chiral state pairs. The chiral excited states manifest as chiral splitting of the Kondo peak in the spectral function. The theoretical analysis is confirmed by the numerical computations. Furthermore, under a Zeeman magnetic field B, the chiral Kondo peak splits into four peaks, owing to the splitting of spin freedom. The influence of spin chirality on the Kondo effect signifies an important role of the phase factor. This work provides insight into the quantum transport of strongly correlated electronic systems. 相似文献
6.
Madhura Marathe Jérôme Lagoute Vincent Repain Sylvie Rousset Shobhana Narasimhan 《Surface science》2012,606(11-12):950-955
We have studied electronic structure of Fe-deposited Au(111) by performing ab initio density functional theory calculations. We find that the magnetic moment on the deposited Fe layer is enhanced as compared to that in bulk iron. We observe a large number of new states on the Fe-deposited surface — one of which is in the majority spin channel having similar dispersion to that on the clean surface, and others in the minority spin channel. The effective mass of electrons in surface states near the Fermi level increases on Fe deposition. The electronic properties are found to be insensitive to the stacking of near-surface layers. We need to use very thick slabs in our calculations to avoid splitting of surface states due to spurious interactions between the two surfaces of the slab. Using the local density of states profiles for different surface states, we conclude that in scanning tunneling microscope experiments one can detect two of the surface states — one in the majority channel below the Fermi level, and another in the minority channel appearing just above the Fermi energy. We compare our results to those from scanning tunneling spectroscopy experiments. 相似文献
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Shikin AM Varykhalov A Prudnikova GV Usachov D Adamchuk VK Yamada Y Riley JD Rader O 《Physical review letters》2008,100(5):057601
Spin-orbit coupling can give rise to spin-split electronic states without a ferromagnet or an external magnetic field. We create large spin-orbit splittings in a Au and Ag monolayer on W(110) and show that the size of the splitting does not depend on the atomic number of the Au or Ag overlayer but of the W substrate. Spin- and angle-resolved photoemission and Fermi-surface scans reveal that the overlayer states acquire spin polarization through spin-dependent overlayer-substrate hybridization. 相似文献
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Ast CR Henk J Ernst A Moreschini L Falub MC Pacilé D Bruno P Kern K Grioni M 《Physical review letters》2007,98(18):186807
The long-range ordered surface alloy Bi/Ag(111) is found to exhibit a giant spin splitting of its surface electronic structure due to spin-orbit coupling, as is determined by angle-resolved photoelectron spectroscopy. First-principles electronic structure calculations fully confirm the experimental findings. The effect is brought about by a strong in-plane gradient of the crystal potential in the surface layer, in interplay with the structural asymmetry due to the surface-potential barrier. As a result, the spin polarization of the surface states is considerably rotated out of the surface plane. 相似文献
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Sänger I Yakovlev DR Pisarev RV Pavlov VV Bayer M Karczewski G Wojtowicz T Kossut J 《Physical review letters》2006,96(11):117211
Basically different mechanisms of optical second harmonic generation (SHG) in semiconductors, induced by an external magnetic field H, have been identified experimentally by studying the diluted magnetic semiconductor (Cd,Mn)Te. For paramagnetic (Cd,Mn)Te the SHG response is governed by spin quantization of electronic states, in contrast with diamagnetic CdTe with its dominating orbital quantization. The mechanisms can be identified by the distinct magnetic field dependence of the SHG intensity which scales with the spin splitting in the paramagnetic case as compared to the H2 dependence observed for the diamagnetic case. 相似文献
10.
Martin Breza 《Czechoslovak Journal of Physics》1990,40(11):1177-1184
Classification of the stable symmetries of Jahn-Teller systems ofI
h parent group is elaborated for triply, fourfold and fivefold degenerate electronic states with integer spin and for fourfold and sixfold degenerate ones with non-integer spin. The results produced by the epikernel principle and by the method of step-by-step descent in symmetry connected with degenerate states splitting are compared. The results obtained on the basis of epikernel principle are incomplete and may even be incorrect. 相似文献
11.
We have studied the electronic structures of quasi-two-dimensional buckled honeycomb silicon (BHS) saturated by atomic hydrogen and fluorine by means of first-principles calculations. The graphene-like hexagonal silicon with chair configurations can be stabilized by atomic hydrogen and fluorine adsorption. Together with a magnetic ground state, large spin–orbit coupling (SOC) of BHS saturated by hydrogen on either side (Semi-H-BHS) indicated by the band splitting of σ bond at Γ point in the Brillouin zone is attributed to the intermixing between the density of states of hydrogen atoms and π bonds of unpassivated Si2 around the Fermi level. The Zeeman spin splitting is most likely caused by the internal electric field induced by asymmetric charge transfer. 相似文献
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Effect of C, N or O adsorption on ferromagnetic Co(0 0 0 1) surface on evolution of important electronic features is studied within the local-density functional scheme. At high oxygen or carbon coverage, the spin asymmetry of Co(3d) states at the Fermi level can be reversed; for oxygen, however, the effect is not stable with respect to geometry variation and might correspond to non-equilibrium adatom positions. The concept of exchange splitting for non-homogeneous systems is poorly defined and its presence for well distinguished peaks in the local density of adatom 2p states is expected especially for oxygen. The calculations find, nevertheless, a simple and accurate relation between the spin-splitting of the centre of gravity of 2p electronic sates and value of the magnetic moment induced on adatoms. 相似文献
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We built electron and phonon free energies and attempted to investigate the effect of the electron-phonon interaction on giant magnetoresistance in magnetic multilayers. Starting from a jellium-like model, we found that the electron-phonon interaction can have an important effect on the spin splitting of electronic energy band. The expression of giant magnetoresistance has been obtained by considering the spin splitting of electronic energy band,indicating that the effect of phonon could not be neglected. Numerical calculations using our approach demonstrate the agreement between experimental and theoretical values. 相似文献
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Angle-resolved photoemission is used to determine the change in the electronic states of Ni induced by doping with Fe and Cr. Well-defined spin and k states are selected using high energy and k resolution combined with single crystal alloys. Iron suppresses the mean free path of minority spins only, while chromium suppresses both spins and decreases the magnetic splitting. The strong variation of these effects from one impurity to the other supports the concept of magnetic doping. 相似文献
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In transition metal compounds with spin states close in energy, the magnitude and sign of the energy splitting calculated with density functional theory depends strongly on the functional used. Therefore we must turn to additional criteria to assess the level of accuracy and reliability of predictions based on this level of theory. We report optimized geometries, total energies, and Mössbauer quadrupole splitting values for low-spin and high-spin, ferric and ferrous model hemes using a variety of gradient-corrected and hybrid functionals. In one model, the iron–porphyrin is axially ligated by two strong-field imidazole ligands [FeP(Im)2] and has a low-spin ground state. In the other model complex the axial ligands are two weak-field, water molecules [FeP(H2O)2], and have a high-spin ground state. Among all the functionals used (UHF, B3LYP, B3LYP*, BLYP, half-and-half, LSDA), the B3LYP hybrid functional most consistently reproduced the experimental geometry, Mössbauer, and spin state data for the two model hemes. Simply gradient-corrected functionals exhibit strong biases towards low spin states, while Hartree–Fock favours strongly high spin states. These findings suggest that for systems with similar characteristics of several accessible electronic spin configurations, it is imperative to include properties other than just the energy in the assessment of the DFT predictions. 相似文献
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Comparison of calculation methods for the tunnel splitting at excited states of biaxial spin models 下载免费PDF全文
We present the calculation and comparison of tunnel splitting at excited levels of biaxial spin models by various methods, including the generalized instanton method, the generalized path integral method for coherent spin states, the perturbation method, and the exact method by numerical diagonalization of the Hamiltonian. It is found that, for integer spin with spin number around 10, tunnel splitting predicted by the generalized path integral for coherent spin states is about 10^{-n} times of the exact numerical result for the nth excited level, while the ratio of the results of the perturbation method and the exact numerical method diverges in the large spin limit. We thus conclude that the generalized instanton method is the best approximate way for calculating tunnel splitting in spin models. 相似文献
18.
Fuchs GD Dobrovitski VV Hanson R Batra A Weis CD Schenkel T Awschalom DD 《Physical review letters》2008,101(11):117601
We use single-spin resonant spectroscopy to study the spin structure in the orbital excited state of a diamond nitrogen-vacancy (N-V) center at room temperature. The data show that the excited-state spin levels have a zero-field splitting that is approximately half of the value of the ground state levels, a g factor similar to the ground state value, and a hyperfine splitting approximately 20x larger than in the ground state. In addition, the width of the resonances reflects the electronic lifetime in the excited state. We also show that the spin level splitting can significantly differ between N-V centers, likely due to the effects of local strain, which provides a pathway to control over the spin Hamiltonian and may be useful for quantum-information processing. 相似文献
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It has been found in the triplet E.S.R. spectra of radical pairs in irradiated potassium deuterium fumarate that the hyperfine structure of the two transitions, M s = 1?0 and M s = 0?+1, are entirely different. This anomaly has been interpreted in terms of the forbidden transition arising from the mixing of the nuclear spin states by the anisotropic hyperfine interaction. The theory has been developed for multiplet electron spin systems and includes the nuclear Zeeman interaction which is often neglected. The theoretical predictions are in good agreement with the observed separations and intensities of the anomalous hyperfine lines. In addition, it has been found that since the forbidden lines of the electron spin multiplet system with S ≥ 1 appear strongly only in transitions which include some specific electronic spin states, the anomalous features of the spectra make it possible to determine the absolute sign of the zero-field or hyperfine splitting constant, if the sign for one of them is known. Using this principle, attempts have been made to determine the absolute sign of the zero-field splitting constant for a number of triplet E.S.R. spectra which exhibit a hyperfine anomaly arising from the proposed mechanism. 相似文献