Effect of Sb substitution on the Topological Surface States in Bi_{2}Se_{3} single crystals: a magneto-transport study

TL;DR

This study investigates how substituting Sb in Bi2Se3 single crystals affects their topological surface states, revealing a decrease in Fermi surface area and the emergence of 2D surface states through magneto-transport measurements.

Contribution

It provides new insights into how Sb substitution modulates the topological surface states and electronic properties of Bi2Se3, using detailed magneto-transport analysis.

Findings

Observation of 2D SdH oscillations up to x=0.3 Sb concentration

Systematic decrease in Fermi surface area with Sb substitution

Identification of topological surface states and surface 2D electron gas at higher Sb levels

Abstract

Magneto-transport measurements have been carried out on Bi2-xSbxSe3 (x = 0, 0.05, 0.1, 0.3, 0.5) single crystals at 4.2 K temperature in the magnetic field range of -15 T to 15 T. Shubnikov-de Haas (SdH) oscillations of 2D nature were observed in samples with Sb concentration upto x = 0.3. The analyses of SdH oscillations observed in magneto-resistance data using Lifshitz-Kosevich equation reveal a systematic decrease in the Fermi surface area with Sb substitution. The Berry phase obtained from the Landau Level fan diagram suggests the occurrence of 2D oscillations arising from a Topological Surface State (TSS) for Sb concentrations of x = 0, 0.05 and 0.1; while 2D oscillation seen at higher Sb concentration is attributed to surface 2D electron gas consequent to downward band bending.