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A two-dimensional honeycomb lattice harbours a pair of inequivalent valleys in the k-space electronic structure, in the vicinities of the vertices of a hexagonal Brillouin zone, K(±). It is particularly appealing to exploit this emergent degree of freedom of charge carriers, in what is termed 'valleytronics'. The physics of valleys mimics that of spin, and(More)
AIM To observe the effects of extracts of Ginkgo biloba leaves (EGb) on the Parkinson disease (PD) models induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its ion 1-methyl-4-phenylpyridinium (MPP+). METHODS MPTP was microinjected into substantia nigra of rats to induce a behavior change of rotation. EGb (ip, 50 or 100 mg.kg(1 . d-1) was(More)
Liouville's theorem on the conservation of phase-space volume is violated by Berry phase in the semiclassical dynamics of Bloch electrons. This leads to a modification of the phase-space density of states, whose significance is discussed in a number of examples: field modification of the Fermi-sea volume, connection to the anomalous Hall effect, and a(More)
We obtain a set of general formulas for determining magnetizations, including the usual electromagnetic magnetization as well as the gravitomagnetic energy magnetization. The magnetization corrections to the thermal transport coefficients are explicitly demonstrated. Our theory provides a systematic approach for properly evaluating the thermal transport(More)
In anesthetized thoracotomized dogs, rhynchophylline (Rhy 5 mg.kg-1, iv) reduced the mean arterial pressure (MAP), heart rate (HR), and coronary blood flow (CBF) by 1.16 +/- s 0.67 kPa, 19 +/- 12 beats/min, and 0.12 +/- 0.04 ml.min-1.g-1, whereas isorhynchophylline (Isorhy 1 mg.kg-1, iv) reduced the parameters by 3.58 +/- 0.19 kPa, 26 +/- 18 beats/min, and(More)
  • Junren Shi, Ping Zhang, Di Xiao, Qian Niu
  • Physical review letters
  • 2006
The conventional definition of spin current is incomplete and unphysical in describing spin transport in systems with spin-orbit coupling. A proper and measurable spin current is established in this study, which fits well into the standard framework of near-equilibrium transport theory and has the desirable property to vanish in insulators with localized(More)
A magnetoconductivity formula is presented for the surface states of a magnetically doped topological insulator. It reveals a competing effect of weak localization and weak antilocalization in quantum transport when an energy gap is opened at the Dirac point by magnetic doping. It is found that, while random magnetic scattering always drives the system from(More)
We study the possibility of realizing topological phases in graphene with randomly distributed adsorbates. When graphene is subjected to periodically distributed adatoms, the enhanced spin-orbit couplings can result in various topological phases. However, at certain adatom coverages, the intervalley scattering renders the system a trivial insulator. By(More)
We demonstrate that the radiation-induced "zero-resistance state" observed in a two-dimensional electron gas is a result of the nontrivial structure of the density of states of the systems and the photon-assisted transport. A toy model of a quantum tunneling junction with oscillatory density of states in leads catches most of the important features of the(More)
Conventional electronics are based invariably on the intrinsic degrees of freedom of an electron, namely its charge and spin. The exploration of novel electronic degrees of freedom has important implications in both basic quantum physics and advanced information technology. Valley, as a new electronic degree of freedom, has received considerable attention(More)