Catalyst-Free Growth of Millimeter-Long Topological Insulator Bi2Se3 Nanoribbons and the Observation of pi Berry Phase

TL;DR

This paper reports a catalyst-free method to grow long, high-purity Bi2Se3 nanoribbons, enabling detailed study of their topological surface states and the observation of the pi Berry phase associated with Dirac fermions.

Contribution

It introduces a catalyst-free physical vapor deposition technique for growing millimeter-long Bi2Se3 nanoribbons and provides detailed electronic structure characterization including Berry phase measurement.

Findings

Successful growth of millimeter-long Bi2Se3 nanoribbons

Observation of pi Berry phase in topological surface states

Dominant two-dimensional surface state contribution in magneto-transport

Abstract

We report the growth of single-crystalline Bi2Se3 nanoribbons with lengths up to several millimeters via a catalyst-free physical vapor deposition method. Scanning transmission electron microscopy analysis reveals that the nanoribbons grow along the (1120) direction. We obtain a detailed characterization of the electronic structure of the Bi2Se3 nanoribbons from measurements of Shubnikov-de Haas (SdH) quantum oscillations. Angular dependent magneto-transport measurements reveal a dominant two-dimensional contribution originating from surface states and weak contribution from the bulk states. The catalyst-free synthesis yields high-purity nanocrystals enabling the observation of a large number of SdH oscillation periods and allowing for an accurate determination of the pi-Berry phase, one of the key features of Dirac fermions in topological insulators. The long-length nanoribbons can empower the potential for fabricating multiple nanoelectronic devices on a single nanoribbon.