Crossover of Three-Dimensional Topological Insulator of Bi2Se3 to the Two-Dimensional Limit (2009)
Zhang, Yi, He, Ke, Chang, Cui-Zu, Song, Can-Li, Wang, Lili, Chen, Xi, ...
Bi2Se3 is theoretically predicted1 and experimentally observed2,3 to be a three dimensional topological insulator. For possible applications, it is important to understand the electronic structure of...
Electric field modulation of topological order in thin film semiconductors (2009)
Jiang, Zhan-Feng, Chu, Rui-Lin, Shen, Shun-Qing
We propose a method that can consecutively modulate the topological orders or the number of helical edge states in ultrathin film semiconductors without a magnetic field. By applying a staggered...
Disorder effect of resonant spin Hall effect in a tilted magnetic field (2009)
Jiang, Zhan-Feng, Shen, Shun-Qing, Zhang, Fu-Chun
We study the disorder effect of resonant spin Hall effect in a two-dimension electron system with Rashba coupling in the presence of a tilted magnetic field. The competition between the Rashba...
Quantum Hall effect of the surface states in topological insulator (2009)
We study the quantum Hall effect in the surface states of topological insulator in the presence of a perpendicular magnetic field in the framework of edge states. Motion of Dirac fermions will form...
Predicted emergent spin physics in an ultrathin film of topological insulator (2009)
Lu, Hai-Zhou, Shan, Wen-Yu, Yao, Wang, Niu, Qian, Shen, Shun-Qing
We study transport and optical properties of the surface states which lie in the bulk energy gap of a thin-film topological insulator. When the film thickness is comparable with the surface state...
Li, Peng, Su, Haibin, Dong, Hui-Ning, Shen, Shun-Qing
We study a triangular frustrated antiferromagnetic Heisenberg model with nearest-neighbor interaction $J_{1}$ and third-nearest-neighbor interactions $J_{3}$ by means of Schwinger-boson mean-field...
Chu, Rui-Lin, Li, Jian, Jain, J. K., Shen, Shun-Qing
The topological insulators have a gap in the bulk but extended states at the edge that can carry current. We study a geometry in which such edge states will manifest themselves through periodic...
Detecting and Switching Magnetization of Stoner Nanograin in Non-local Spin Valve (2009)
The magnetization detection and switching of an ultrasmall Stroner nanograin in a non-local spin valve (NLSV) device is studied theoretically. By considering spin diffusive and tunneling transport in...
Spin relaxation in sub-monolayer and monolayer InAs structures grown in GaAs matrix (2009)
Yang, Chunlei, Cui, Xiaodong, Shen, Shun-Qing, Xu, Zhongying, Ge, Weikun
Electron spin dynamics in InAs/GaAs heterostructures consisting of a single layer of InAs (1/3$\sim$1 monolayer) embeded in (001) and (311)A GaAs matrix was studied by means of time-resolved Kerr...
Lu, Hai-Zhou, Zhou, Bin, Shen, Shun-Qing
Magnetization reversal in a single molecular magnet (SMM) weakly coupled to an electrode with spin-dependent splitting of chemical potentials (spin bias) is theoretically investigated by means of the...
Topological Anderson Insulator (2008)
Li, Jian, Chu, Rui-Lin, Jain, J. K., Shen, Shun-Qing
Disorder plays an important role in two dimensions, and is responsible for striking phenomena such as metal insulator transition and the integral and fractional quantum Hall effects. In this paper,...
Double quantum dot as detector of spin bias (2008)
Sun, Qing-feng, Xing, Yanxia, Shen, Shun-Qing
It was proposed that a double quantum dot can be used to be a detector of spin bias. Electron transport through a double quantum dot is investigated theoretically when a pure spin bias is applied on...
Disorder Effects in the Quantum Hall Effect of Graphene p-n Junctions (2008)
The quantum Hall effect in graphene p-n junctions is studied numerically with emphasis on the effect of disorder at the interface of two adjacent regions. Conductance plateaus are found to be...
Finite size effects of helical edge states in HgTe/CdTe quantum wells (2008)
Zhou, Bin, Lu, Hai-Zhou, Chu, Rui-Lin, Shen, Shun-Qing, Niu, Qian
The solutions for the helical edge states for an effective continuum model for the quantum spin Hall effect in HgTe/CdTe quantum wells are presented. For a sample of a large size, the solution gives...
Conductance plateau in quantum spin transport through an interacting quantum dot (2008)
Bao, Yun-Juan, Tong, Ning-Hua, Sun, Qing-Feng, Shen, Shun-Qing
Quantum spin transport is studied in an interacting quantum dot. It is found that a conductance "plateau" emerges in the non-linear charge conductance by a spin bias in the Kondo regime. The...
Using spin bias to manipulate and measure quantum spin in quantum dots (2008)
A double-quantum-dot coupled to electrodes with spin-dependent splitting of chemical potentials (spin bias) is investigated theoretically by means of the Green's functions formalism. By applying a...
Current-induced Spin Polarization in Two-Dimensional Hole Gas (2007)
Liu, Chao-Xing, Zhou, Bin, Shen, Shun-Qing, Zhu, Bang-fen
We investigate the current-induced spin polarization in the two-dimensional hole gas (2DHG) with the structure inversion asymmetry. By using the perturbation theory, we re-derive the effective...
The Kagome Antiferromagnet: A Schwinger-Boson Mean-Field Theory Study (2007)
Li, Peng, Su, Haibin, Shen, Shun-Qing
The Heisenberg antiferromagnet on the Kagom\'{e} lattice is studied in the framework of Schwinger-boson mean-field theory. Two solutions with different symmetries are presented. One solution gives a...
Spin polarized current in a junction of zigzag carbon nanotube (2007)
Jiang, Zhan-Feng, Li, Jian, Shen, Shun-Qing, Liu, W. M.
We investigated spin-resolved electronic transport through a junction composed of a nonmagnetic metal electrode and a zigzag carbon nanotube by means of self-consistent Green's function method in the...
Observation of electric current induced by optically injected spin current (2007)
Cui, Xiao-Dong, Shen, Shun-Qing, Li, Jian, Ji, Yang, Ge, Wei-Kun, Zhang, Fu-Chun
Linearly polarized light at normal incidence injects a spin current into a strip of two-dimensional electron gas with Rashba spin-orbit coupling. The authors report observation of an electric current...
Zhou, Bin, Liu, Chao-Xing, Shen, Shun-Qing
We propose a topological quantum phase transition for quantum states with different Berry phases in hole-doped III-V semiconductor quantum wells with bulk and structure inversion asymmetry. The Berry...
Theory of resonant spin Hall effect (2007)
Zhang, Fu-Chun, Shen, Shun-Qing
A biref review is presented on resonant spin Hall effect, where a tiny external electric field induces a saturated spin Hall current in a 2-dimensional electron or hole gas in a perpendicular...
Spin transverse force and quantum transverse transport (2007)
We present a brief review on spin transverse force, which exerts on the spin as the electron is moving in an electric field. This force, analogue to the Lorentz force on electron charge, is...
This is a reply to W. Zawadzki's paper (arXiv: cond-mat/0701378) on non-exietence of spin transverse force for a relativistic electron. The force was first proposed by the present author that the...
We demonstrate that the flow of a longitudinal spin current with different spin polarization will induce different patterns of charge accumulation in a two-terminal strip, or electric current...
We study the spin photogalvanic effect in two-dimensional electron system with structure inversion asymmetry by means of the solution of semiconductor optical Bloch equations. It is shown that a...
Electric-Field-Induced Resonant Spin Polarization in a Two-Dimensional Electron Gas (2006)
Bao, Yun-Juan, Shen, Shun-Qing
Electric response of spin polarization in two-dimensional electron gas with structural inversion asymmetry subjected to a magnetic field was studied by means of the linear and non-linear theory and...
Yao, Yugui, Liang, Yongcheng, Xiao, Di, Niu, Qian, Shen, Shun-Qing, Dai, X., ...
To justify the origin of anomalous Hall effect (AHE), it is highly desirable to have the system parameters tuned continuously. By quantitative calculations, we show that the doping dependent sign...
Observation of electric current induced by optically injected spin current (2006)
Cui, Xiao-Dong, Shen, Shun-Qing, Li, Jian, Ge, Weikun, Zhang, Fu-Chun
A normally incident light of linear polarization injects a pure spin current in a strip of 2-dimensional electron gas with spin-orbit coupling. We report observation of an electric current with a...
Li, Peng, Zhang, Guang-Ming, Shen, Shun-Qing
A bond-operator mean-field theory in the SU(3) bosons representation is developed to describe the antiferro-nematic phase of the spin-1 bilinear-biquadratic model. The calculated static structure...
Spin transverse force and intrinsic quantum transverse transport (2006)
Zhou, Bin, Ren, Li, Shen, Shun-Qing
The spin-orbit coupling may generate spin transverse force on moving electron spin, which gives a heuristic picture for the quantum transverse transport of electron. A relation between the spin and...
Spin-Hall effect: Back to the Beginning on a Higher Level (2005)
Sinova, Jairo, Murakami, Shuichi, Shen, Shun-Qing, Choi, Mahn-Soo
The phenomena of the spin-Hall effect, initially proposed over three decades ago in the context of asymmetric Mott skew scattering, was revived recently by the proposal of a possible intrinsic...
Li, Jian, Dai, Xi, Shen, Shun-Qing, Zhang, Fu-Chun
We examine electric response of a linearly polarized light normally shed on a cross-shaped quasi 2-dimensional InGaAs/InAlAs system with structure inversion asymmetry. The photo-excited conduction...
A generalized one-dimensional $SU(2)\times SU(2)$ spin-orbital model is studied by Schwinger boson mean-field theory (SBMFT). We explore mainly the dimer phases and clarify how to capture properly...
Spin transverse force on spin current in an electric field (2005)
As a relativistic quantum mechanical effect, it is shown that the electric field exerting a transverse force on an electron spin 1/2 only if the electron is moving and the spin is polarized along the...
Hankiewicz, E. M., Li, Jian, Jungwirth, Tomas, Niu, Qian, Shen, Shun-Qing, Sinova, Jairo
We study theoretically the spin-Hall effect as well as its reciprocal phenomenon (a transverse charge current driven by a spin-dependent chemical potential gradient) in electron and hole finite size...
Edge Spin Current and Spin Polarization in Quantum Hall Regime (2005)
Bao, Yun-Juan, Zhuang, Huai-Bing, Shen, Shun-Qing, Zhang, Fu-Chun
We study the edge spin current and spin polarization in a two-dimensional electron gas with spin-orbit coupling in the presence of a perpendicular magnetic field. The edge effect removes the...
Spin resolved Hall effect driven by spin-orbit coupling (2005)
Li, Jian, Hu, Liangbin, Shen, Shun-Qing
Spin and electric Hall currents are calculated numerically in a two-dimensional mesoscopic system with Rashba and Dresselhaus spin-orbit coupling by means of the Landauer-Buttiker formalism. It is...
Contractor renormalization group theory of the SU($N$) chains and ladders (2004)
Contractor renormalization group (CORE) method is applied to the SU($N$) chain and ladders in this paper. In our designed schemes, we show that these two classes of systems can return to their...
Two-dimensional gapless spin liquids in frustrated SU(N) quantum magnets (2004)
A class of the symmetrically frustrated SU(N) models is constructed for quantum magnets based on the generators of SU(N) group. The total Hamiltonian lacks SU(N) symmtry. A mean field theory in the...
Shen, Shun-Qing, Bao, Yun-Juan, Ma, Michael, Xie, X. C., Zhang, Fu Chun
Following a previous work [Shen, Ma, Xie and Zhang, Phys. Rev. Lett. 92, 256603 (2004)] on the resonant spin Hall effect, we present detailed calculations of the spin Hall conductance in...
Controllable quantum spin precession by Aharonov-Casher phase in conducting ring (2004)
Shen, Shun-Qing, Li, Zhi-Jian, Ma, Zhongshui
We investigate quantum spin transport in a structure of conducting ring, embedded in textured electric field, with two leads, and obtain an exact solution for the problem. The spin precession induced...
Ma, Xiaohua, Hu, Liangbin, Tao, Ruibao, Shen, Shun-Qing
In a two dimensional electron gas with Rashba spin-orbit coupling, the external electric field may cause a spin Hall current in the direction perpendicular to the electric field. This effect was...
Conductance modulation in spin field-efect transistors under finite bias voltages (2004)
Hu, Liangbin, Gao, Ju, Shen, Shun-Qing
The conductance modulations in spin field-effect transistors under finite bias voltages were studied. It was shown that when a finite bias voltage is applied between two terminals of a spin...
Charge ordering and phase separation in the infinite dimensional extended Hubbard model (2004)
Tong, Ning-Hua, Shen, Shun-Qing, Bulla, Ralf
We study the extended Hubbard model with both on-site (U) and nearest neighbor (V) Coulomb repulsion using the exact diagonalization method within the dynamical mean field theory. For a fixed U...
Shen, Shun-Qing, Ma, Michael, Xie, X. C., Zhang, Fu Chun
We study transport properties of a two-dimensional electron system with Rashba spin-orbit coupling in a perpendicular magnetic field. The spin orbit coupling competes with Zeeman splitting to...
Hu, Liangbin, Gao, Ju, Shen, Shun-Qing
It was proposed recently by Murakami et al. [Science \textbf{301}, 1348(2003)] that in a large class of $p$-doped semiconductors, an applied electric field can drive a quantum dissipationless spin...
Zhou, Bin, Tao, Ruibao, Shen, Shun-Qing
Quantum-classical escape rate transition has been studied for uniaxial antiferromagnetic particles with an arbitrarily directed magnetic field. In the case that the transverse and longitudinal fileds...
Spin Hall effect and Berry phase in two dimensional electron gas (2003)
The spin Hall effect is investigated in a high mobility two dimensional electron system with the spin-orbital coupling of both the Rashba and the Dresselhaus types. A spin current perpendicular to...
SU(4) Spin-Orbital Two-Leg Ladder, Square and Triangle Lattices (2002)
Based on the generalized valence bond picture, a Schwinger boson mean field theory is applied to the symmetric SU(4) spin-orbital systems. For a two-leg SU(4) ladder, the ground state is a...
Renormalized tunnel splitting with a finite distribution in the biaxial spin model for molecular magnets is obtained by taking into account the dipolar interaction of enviromental spins. Oscillation...
Quantum computing of molecular magnet Mn$_{12}$ (2002)
Zhou, Bin, Tao, Ruibao, Shen, Shun-Qing, Liang, Jiu-Qing
Quantum computation in molecular magnets is studied by solving the time-dependent Schr\"{o}dinger equation numerically. Following Leuenberger and Loss (Nature (London) 410, 789(2001)), an external...
Theory for high spin systems with orbital degeneracy (2001)
Shen, Shun-Qing, Xie, X. C., Zhang, F. C.
High-spin systems with orbital degeneracy are studied in the large spin limit. In the absence of Hund's coupling, the classical spin model is mapped onto disconnected orbital systems with spins up...
Formation of energy gap in higher dimensional spin-orbital liquids (2001)
Shen, Shun-Qing, Zhang, Guang-Ming
A Schwinger boson mean field theory is developed for spin liquids in a symmetric spin-orbital model in higher dimensions. Spin, orbital and coupled spin-orbital operators are treated equally. We...
Ordered valence bond states in symmetric two-dimensional spin-orbital systems (2001)
Zhang, Guang-Ming, Shen, Shun-Qing
We consider a superexchange Hamiltonian, $H=-\sum_{}(2{\bf S}_i\cdot {\bf S}_j-\frac 12)(2{\bf T}_i\cdot {\bf T}_j-\frac 12)$, which describes systems with orbital degeneracy and strong...
Mott-Hubbard transition in infinite dimensions (2001)
Tong, Ning-Hua, Shen, Shun-Qing, Pu, Fu-Cho
We analyze the unanalytical structure of metal-insulator transition (MIT) in infinite dimensions. By introducing a simple transformation into the dynamical mean-field equation of Hubbard model, a...
A spin-1/2 system with double orbital degeneracy may possess SU(4) symmetry. According to the group theory a global SU(4) singelt state can be expressed as a linear combination of all possible...
Coloumb interaction and instability of CE-structure in half doped manganites (2001)
In their Letter (Phys. Rev. Lett. 83, 5118 (1999)), den Brink, Khaliullin, and Khomskii proposed theoretically that the one-dimensional ferromagnetic zigzag chains in CE phase in half-doped...
Percolative conductivity and critical exponents in mixed-valent manganites (2001)
Xiong, Ye, Shen, Shun-Qing, Xie, X. C.
Recent experiments have shown that some colossal magnetoresistance (CMR) materials exhibit a percolation transition. The conductivity exponent varies substantially with or without an external...
Linear spin and orbital wave theory for undoped manganites (1999)
Gu, R. Y., Shen, Shun-Qing, Wang, Z. D., Xing, D. Y.
We present a linear spin and orbital wave theory to account for the spin and orbital orderings observed experimentally in undoped manganite. It is found that the anisotropy of the magnetic structure...
Unified theory of phase separation and charge ordering in doped manganite perovskites (1999)
A unified theory is developed to explain various types of electronic collective behaviors in doped manganites R$_{1-x}$X$_x$MnO$_3$ (R = La, Pr,Nd etc. and X = Ca, Sr, Ba etc.). Starting from a...
Gu, R. Y., Wang, Z. D., Shen, Shun-Qing, Xing, D. Y.
We investigate the phase diagram of an extended Kondo lattice model for doped manganese oxides in the presence of strong but finite Hund's coupling and on-site Coulomb interaction. By means of the...
An effective Hamiltonian is derived in the case of the strong Hund coupling and on-site Coulomb interaction by means of a projective perturbation approach. A physical mechanism for charge ordering in...
We present an exact ground state solution of a one-dimensional electronic model for transition-metal oxides in the strong coupling limit. The model contains doubly degenerated orbit for itinerant...
We investigate the ground state properties of electronic models for doped manganites and nickelates. An effective t - J like Hamiltonian is derived from the case of strong Hund coupling between the...
The ground state of the Kondo model with large spin (1997)
In this paper, we prove that the ground state of the Kondo model with large spin is nondegenerate, apart from a SU(2) spin degeneracy in the case of half filling. The ground state spin is found for...