相关论文: High-frequency nonlinear transport and photogalvan…
We discuss optical absorption in topological insulators and study possible photoelectric effects theoretically. We found that absorption of circularly polarized electromagnetic waves in two-dimensional topological insulators results in…
We report on the observation of a circular photogalvanic current excited by terahertz (THz) laser radiation in helical edge channels of HgTe-based 2D topological insulators (TIs). The direction of the photocurrent reverses by switching the…
We study theoretically 2D HgTe/CdTe quantum well topological insulator (TI) illuminated by circularly polarized light with frequencies higher than the difference between the equilibrium Fermi level and the bottom of the conduction band (THz…
We develop a theory of electron-photon interaction for helical edge channels in two-dimensional topological insulators based on zinc-blende-type quantum wells. It is shown that the lack of space inversion symmetry in such structures enables…
Theory of the Linear photogalvanic effect is developed for direct optical transitions between surface states of three-dimensional topological insulators. The photocurrent governed by the orientation of the polarization plane of light and…
We report on the observation of complex nonlinear intensity dependence of the circular and linear photogalvanic currents induced by infrared radiation in compensated (Bi$_{0.3}$Sb$_{0.7}$)$_2$(Te$_{0.1}$Se$_{0.9}$)$_3$ 3D topological…
We consider the helical edge state of a Quantum Spin Hall insulator, connected between two leads, and irradiated by a monochromatic and circularly polarized electromagnetic wave. The photocurrent generated within the helical edge state is…
We describe the observation of the circular and linear photogalvanic effects in HgTe/CdHgTe quantum wells. The interband absorption of mid-infrared radiation as well as the intrasubband absorption of terahertz (THz) radiation in the QWs…
We show that the inter-band absorption of radiation in a 2D Dirac material leads to a direct electric current flowing at sample edges. The photocurrent originates from the momentum alignment of electrons and holes and is controlled by the…
Circularly polarized photons are known to generate a directional helicity-dependent photocurrent in three-dimensional topological insulators at room temperature. Surprisingly, the phenomenon is readily observed at photon energies that…
We report on the observation of photogalvanic effects in epitaxially grown Sb_2Te_3 three-dimensional (3D) topological insulators (TI). We show that asymmetric scattering of Dirac electrons driven back and forth by the terahertz electric…
We demonstrate, theoretically and experimentally, that a traveling electric charge passing from one photonic crystal into another generates edge waves -- electromagnetic modes with frequencies inside the common photonic bandgap localized at…
We study the stationary surface photocurrent in 2D electron gas near the helium surface. Electron gas is assumed to be attracted to the helium surface due to the image attracting force and an external stationary electric field. The…
We study theoretically transverse photoconductivity induced by circularly polarized radiation, i.e. the photovoltaic Hall effect, and linearly polarized radiation causing intraband optical transitions in two-dimensional electron gas (2DEG).…
An unusual photo-galvanic effect is predicted on the topological insulator surface when its semi-metallic electronic spectrum is modified by an adjacent ferromagnet. The effect is correlated with light absorption in a wide frequency range…
We outline here how strong light-matter interaction can be used to induce quantum phase transition between normal and topological phases in two-dimensional topological insulators. We consider the case of a HgTe quantum well, in which band…
We study laser driven spin-current effects at ferromagnet/topological-insulator interfaces by two complementary experimental approaches. The DC photocurrent is studied in ferromagnet/topological-insulator bilayers with high spatial…
We report on a strong nonlinear behavior of the photogalvanics and photoconductivity under excitation of HgTe quantum wells (QWs) by intense terahertz (THz) radiation. The increasing radiation intensity causes an inversion of the sign of…
Three-dimensional topological insulators represent a new quantum phase of matter with spin-polarized surface states that are protected from backscattering. The static electronic properties of these surface states have been comprehensively…
Nonlinear helicity-dependent photocurrents have been reported in 3D topological materials lacking inversion symmetry. Here, we theoretically study the charge and spin photocurrents generated by linear and circularly polarized radiation in…