Band Structure of Topological Insulator BiSbTe1.25Se1.75

Abstract

We present our angle resolved photoelectron spectroscopy (ARPES) and density functional theory results on quaternary topological insulator (TI) BiSbTe1.25Se1.75 (BSTS) confirming the non-trivial topology of the surface state bands (SSBs) in this compound. We find that the SSBs, which are are sensitive to the atomic composition of the terminating surface have a partial 3D character. Our detailed study of the band bending (BB) effects shows that in BSTS the Dirac point (DP) shifts by more than two times compared to that in Bi2Se3 to reach the saturation. The stronger BB in BSTS could be due to the difference in screening of the surface charges. From momentum density curves (MDCs) of the ARPES data we obtained an energy dispersion relation showing the warping strength of the Fermi surface in BSTS to be intermediate between those found in Bi2Se3 and Bi2Te3 and also to be tunable by controlling the ratio of chalcogen/pnictogen atoms. Our experiments also reveal that the nature of the BB effects are highly sensitive to the exposure of the fresh surface to various gas species. These findings have important implications in the tuning of DP in TIs for technological applications.

References in corpus (9)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• First direct observation of Spin-textures in Topological Insulators : Spin-resolved ARPES as a probe of topological quantum spin Hall effect and Berry's phase
• Electrically detected interferometry of Majorana fermions in a topological insulator
• Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3
• Observation of topological surface state quantum Hall effect in an intrinsic three-dimensional topological insulator
• Topological Surface States and Dirac point tuning in ternary Bi2Te2Se class of topological insulators
• Electrostatic Coupling between Two Surfaces of a Topological Insulator Nanodevice
• Dirac states with knobs on: interplay of external parameters and the surface electronic properties of 3D topological insulators

Cited by in corpus (3)

• Signatures of Topological Superconductivity in Bulk Insulating Topological Insulator BiSbTe${}_{1.25}$Se${}_{1.75}$ in Proximity with Superconducting NbSe${}_2$
• Observation of Dirac-like surface state bands on the top surface of BiSe
• Conductance Oscillations in a Topological Insulator-Disordered Superconductor Hybrid Interface