Highly superlinear photogalvanic effects in (Bi${}_{0.3}$Sb${}_{0.7}$)${}_2$(Te${}_{0.1}$Se${}_{0.9}$)${}_3$: Probing 3D topological insulator surface states at room temperature

Abstract

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 insulators. The photocurrents are induced by direct optical transitions between topological surface and bulk states. We show that an increase of the radiation intensity results first in a highly superlinear raise of the amplitude of both types of photocurrents, whereas at higher intensities the photocurrent saturates. Our analysis of the observed nonlinearities shows that the superlinear behavior of the photocurrents is caused by a heating of the electron gas, while the saturation is induced by a slow relaxation of the photoexcited carriers resulting in absorbance bleaching. The observed nonlinearities give access to the Fermi level position with respect to the Dirac point and the energy relaxation times of Dirac fermions providing an experimental room temperature probe for topological surface states.

12 pages, 7 figures

References in corpus (13)

• Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene
• Photocurrents in Weyl semimetals
• Ultrafast helicity control of surface currents in topological insulators with near-unity fidelity
• Ballistic and shift currents in the bulk photovoltaic effect theory
• Quantum ratchet effects induced by terahertz radiation in GaN-based two-dimensional structures
• Shift charge and spin photocurrents in Dirac surface states of topological insulator
• Spin photocurrents and circular photon drag effect in (110)-grown quantum well structures
• Ultrafast Energy- and Momentum-resolved Surface Dirac Photocurrents in the Topological Insulator Sb${}_2$Te${}_3$
• Opto-Electronic Characterization of Three Dimensional Topological Insulators
• High-frequency nonlinear transport and photogalvanic effects in two-dimensional topological insulators
• Edge photocurrent driven by THz electric field in bi-layer graphene
• Nonlinear intensity dependence of terahertz edge photocurrents in graphene
• Transport properties of band engineered p-n heterostructures of epitaxial Bi${}_2$Se${}_3$/(Bi${}_{1-x}$Sb${}_x$)${}_2$(Te${}_{1-y}$Se${}_y$)${}_3$ topological insulators

Cited by in corpus (9)

• Linear photogalvanic effect in surface states of topological insulators
• Nonlinear intensity dependence of photogalvanics and photoconductance induced by terahertz laser radiation in twisted bilayer graphene close to magic angle
• Nonlinear optical absorption and photocurrents in topological insulators
• Bulk-Fermi-Arc Transition Induced Large Photogalvanic Effect in Weyl Semimetals
• Barrier height inhomogeneity and origin of 1/f-noise in topological insulator-based photo-detector
• THz radiation induced circular Hall effect in graphene
• Terahertz spin ratchet effect in magnetic metamaterials
• Tracing Dirac points of topological surface states by ferromagnetic resonance
• Enhanced detection of circularly polarized photons with topological materials