Topological-Metal to Band-Insulator Transition in (Bi1-xInx)2Se3 Thin Films

TL;DR

This study investigates how (Bi1-xInx)2Se3 thin films transition from a topological metal to a trivial insulator through multiple quantum phase changes, revealing potential for tunable topological devices.

Contribution

It identifies and characterizes three distinct quantum phase transitions in (Bi1-xInx)2Se3 thin films as indium content increases, including a transition to a true band insulator.

Findings

Transition from topologically non-trivial metal to trivial metal at x=3-7%.

Metal becomes a variable-range-hopping insulator at x=15%.

System becomes a true band insulator above x=25%.

Abstract

By combining transport and photo emission measurements on (Bi1-xInx)2Se3 thin films, we report that this system transforms from a topologically non-trivial metal into a topologically trivial band insulator through three quantum phase transitions. At x = 3-7%, there is a transition from a topologically non-trivial metal to a trivial metal. At x = 15%, the metal becomes a variable-range-hopping insulator. Finally, above x = 25%, the system becomes a true band insulator with its resistance immeasurably large even at room temperature. This material provides a new venue to investigate topologically tunable physics and devices with seamless gating/tunneling insulators.