Photocurrents in Bi2Se3: bulk versus surface, and injection versus shift currents

Abstract

Optical injection and detection of charge currents can complement conventional transport and photoemission measurements without the necessity of invasive contact that may disturb the system being examined. This is a particular concern for the surface states of a topological insulator. In this work one- and two-color sources of photocurrents are examined in epitaxial, thin films of Bi2Se3. We demonstrate that optical excitation and terahertz detection simultaneously captures one- and two- color photocurrent contributions, as previously not required in other material systems. A method is devised to isolate the two components, and in doing so each can be related to surface or bulk excitations through symmetry. This strategy allows surface states to be examined in a model system, where they have independently been verified with angle-resolved photoemission spectroscopy.

8 pages, 5 figure, journal submission

References in corpus (8)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Emergent quantum confinement at topological insulator surfaces
• Transmission of topological surface states through surface barriers
• Nonlinear optical probe of tunable surface electrons on a topological insulator
• Room temperature high frequency transport of Dirac fermions in epitaxially grown Sb_2Te_3 based topological insulators
• Spatially resolved femtosecond pump-probe study of topological insulator Bi2Se3
• Coherent control of injection currents in high-quality films of Bi2Se3
• Coherent control of optical injection of spin and currents in topological insulators

Cited by in corpus (11)

• Ab initio calculation of the shift photocurrent by Wannier interpolation
• Ultrafast Spin-To-Charge Conversion at the Surface of Topological Insulator Thin Films
• Difference frequency generation in topological semimetals
• Bulk photovoltaic effects in the presence of a static electric field
• Infrared/Terahertz Spectra of the Photogalvanic Effect in (Bi,Sb)Te based Three Dimensional Topological Insulators
• Terahertz electric field driven electric currents and ratchet effects in graphene
• Quantum Interference Control of Photocurrents in Semiconductors by Nonlinear Optical Absorption Processes
• Quantum Interference Control of Carriers and Currents in Zincblende Semiconductors based on Nonlinear Absorption Processes
• Quantum Interference Control of Localized Carrier Distributions in the Brillouin Zone
• Ultrafast dynamics of photocurrents in surface states of 3D topological insulators
• Quantum Transport in Air-stable Na3Bi Thin Films