Fermions Tunneling from Higher-Dimensional Reissner-Nordstr\"om Black Hole: Semiclassical and Beyond Semiclassical Approximation

Based on semiclassical tunneling method, we focus on charged fermions tunneling from higher-dimensional Reissner-Nordstr\"{o}m black hole. We first simplify the Dirac equation by semiclassical approximation, and then a semiclassical Hamilton-Jacobi equation is obtained. Using the Hamilton-Jacobi equation, we study the Hawking temperature and fermions tunneling rate at the event horizon of the higher-dimensional Reissner-Nordstr\"{o}m black hole spacetime. Finally, the correct entropy is calculation by the method beyond semiclassical approximation.Comment: 7 page

The Lax pair for C_2-type Ruijsenaars-Schneider model

We study the C_2 Ruijsenaars-Schneider(RS) model with interaction potential of trigonometric type. The Lax pairs for the model with and without spectral parameter are constructed. Also given are the involutive Hamiltonians for the system. Taking nonrelativistic limit, we obtain the Lax pair of C_2 Calogero-Moser model.Comment: LaTeX2e, 10 pages, some misprints corrected and sections rearrange

Focusing RKKY interaction by graphene P-N junction

The carrier-mediated RKKY interaction between local spins plays an important role for the application of magnetically doped graphene in spintronics and quantum computation. Previous studies largely concentrate on the influence of electronic states of uniform systems on the RKKY interaction. Here we reveal a very different way to manipulate the RKKY interaction by showing that the anomalous focusing - a well-known electron optics phenomenon in graphene P-N junctions - can be utilized to refocus the massless Dirac electrons emanating from one local spin to the other local spin. This gives rise to rich spatial interference patterns and symmetry-protected non-oscillatory RKKY interaction with a strongly enhanced magnitude. It may provide a new way to engineer the long-range spin-spin interaction in graphene.Comment: 9 pages, 4 figure

Spin-dependent tunneling through a symmetric semiconductor barrier: the Dresselhaus effect

Spin-dependent tunneling through a symmetric semiconductor barrier is studied including the k^3 Dresselhaus effect. The spin-dependent transmission of electron can be obtained analytically. By comparing with previous work(Phys. Rev. B 67. R201304 (2003) and Phys. Rev. Lett. 93. 056601 (2004)), it is shown that the spin polarization and interface current are changed significantly by including the off-diagonal elements in the current operator, and can be enhanced considerably by the Dresselhaus effect in the contact regions.Comment: 10 pages, 5 figures, to appear in PR

Artificial Gauge Field and Quantum Spin Hall States in a Conventional Two-dimensional Electron Gas

Based on the Born-Oppemheimer approximation, we divide total electron Hamiltonian in a spinorbit coupled system into slow orbital motion and fast interband transition process. We find that the fast motion induces a gauge field on slow orbital motion, perpendicular to electron momentum, inducing a topological phase. From this general designing principle, we present a theory for generating artificial gauge field and topological phase in a conventional two-dimensional electron gas embedded in parabolically graded GaAs/In$_{x}$Ga$_{1-x}$As/GaAs quantum wells with antidot lattices. By tuning the etching depth and period of antidot lattices, the band folding caused by superimposed potential leads to formation of minibands and band inversions between the neighboring subbands. The intersubband spin-orbit interaction opens considerably large nontrivial minigaps and leads to many pairs of helical edge states in these gaps.Comment: 9 pages and 4 figure