Effect of an in-plane electric field on the magnetotransport in a helical metal

Article

关键词: HGTE QUANTUM-WELLS;    TOPOLOGICAL INSULATOR;    PHASE;    STATE;   

DOI  :  10.1103/PhysRevB.86.041403

来源: SCIE

【 摘 要 】

The existence of helical surface states in a bulk insulator, with anomalous magnetoelectric properties, is a remarkable new development in solid state physics. However clear signatures in transport measurements are lacking. In this paper we report on novel phenomena which provide a route to detecting massless Dirac fermions. The linear dispersion of the the fermions leads to a form of Lorentz invariance, with the Fermi velocity playing the role of the velocity of light (c). In a crossed electromagnetic field, the single-particle states form Landau levels, whose wave functions and energies depend on the applied in-plane electric field but not their degeneracies. We predict the existence of oscillations of conductivity as a function of both the chemical potentials and applied electric field. This is a unique signature of the linear dispersing states due to an even-odd effect where the conductivities of the odd Landau levels are larger than the neighboring even ones. The electric field dependence also leads to testable signatures in steady state thermopower of the nontrivial states.

【 授权许可】

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