Quantum size effects in solitary wires of bismuth

TL;DR

This study investigates quantum size effects in solitary bismuth wires, revealing resistance oscillations and potential phase transition, through detailed electrical measurements and fabrication techniques.

Contribution

It demonstrates the fabrication of ultra-thin bismuth wires and observes quantum size effects and phase transition evidence, expanding understanding of nanoscale semimetal behavior.

Findings

Observation of regular resistance oscillations due to quantum size effects

Evidence suggesting a semimetal-to-semiconductor phase transition

Successful fabrication of single-grain bismuth wires with nanoscale dimensions

Abstract

We have performed four-probe electrical transport measurements on solitary highly crystalline wires of semimetallic bismuth with aspect ratios up to 60 at room and at cryogenic temperatures. By proper choice of the substrate material and the film deposition parameters, lithographic wires with lateral dimensions of down to one single grain, $\sim 250$ nm, were fabricated. The electrical resistance of each wire was measured against its thickness through successive reactive ion etching of the self-same wire. Quantum size effects revealed themselves as regular oscillations in the electrical resistance. Some evidence for the semimetal-to-semiconductor phase transition has been detected. The measured data are discussed within the framework of the existing theoretical models.