相关论文: Helicity dependent photocurrent in electrically ga…
Optical control of helicity-dependent photocurrent in topological insulator Sb$_2$Te$_2$Se has been studied at room temperature on dominantly c-axis oriented granular polycrystalline samples grown by pulsed laser deposition technique.…
One of the most striking manifestations of electronic properties of topological insulators is the dependence of the photocurrent direction on the helicity of circularly polarized optical excitation. The helicity dependent photocurrents,…
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…
Circular photogalvanic currents are a promising new approach for spin-optoelectronics. To date, such currents have only been induced in topological insulator flakes or extended films. It is not clear whether they can be generated in…
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…
Topological insulators constitute a new and fascinating class of matter with insulating bulk yet metallic surfaces that host highly mobile charge carriers with spin-momentum locking. Remarkably, the direction and magnitude of surface…
$\alpha$-Sn exhibits a rich topological phase diagram, yet experimental methods to tune and distinguish these phases remain limited. Here, we investigated the helicity-dependent photocurrent (HDPC) in $\alpha$-Sn films of varying thickness…
Three-dimensional topological insulators are a class of Dirac materials, wherein strong spin-orbit coupling leads to two-dimensional surface states. The latter feature spin-momentum locking, i.e., each momentum vector is associated with a…
Topological insulators (TIs) form a new class of materials with insulating bulk and surface conduction ensured by topologically protected surface states (TPSS). We investigate the impact of the helicity of a normally incident laser beam on…
In view of a study on spin-polarized photodiodes, the helicity-dependent photocurrent in a Fe/x-AlOx/p-GaAs Schottky diode is measured at room temperature by illuminating a circularly polarized light beam (785 nm) either horizontally on the…
We observe enhanced three-fold symmetric helicity-dependent topological photocurrents using time-domain THz spectroscopy in epitaxially-grown Bi2Se3 with reduced crystallographic twinning. It is established how twinned crystal domains…
Recently, a new quantum phase, the topological insulator, has been vividly investigated in a variety of materials. Its unique bandstructure allows for optical generation and control of spin-polarized currents based on the circular…
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 the photocurrent response of topological insulator surface states to circularly polarized light for arbitrary oblique incidence. We describe the surface states within a Dirac model, including several perturbations such as hexagonal…
We report the study of the helicity driven photocurrents in graphene excited by mid-infrared light of a CO$_2$-laser. Illuminating an unbiased monolayer sheet of graphene with circularly polarized radiation generates -- under oblique…
We study theoretically the optical response of the surface states of a topological insulator, especially the generation of helicity-dependent direct current by circularly polarized light. Interestingly, the dominant current, due to an…
Excitation of a topological insulator by a high-frequency electric field of a laser radiation leads to a dc electric current in the helical edge channel whose direction and magnitude are sensitive to the radiation polarization and depend on…
We report on time-resolved ultrafast optical spectroscopy study of the topological insulator (TI) Bi$_2$Se$_3$. We unravel that a net spin polarization can not only be generated using circularly polarized light via interband transitions…
The generation of photocurrent in condensed matter is of main interest for photovoltaic and optoelectronic applications. Shift current, a nonlinear photoresponse, has attracted recent intensive attention as a dominant player of bulk…
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…