# Magnetoconductance Oscillations in Topological Crystalline Insulator Nanowires

## TL;DR

This paper studies the transport properties of Pb1–xSnxTe nanowires and finds evidence of phase-coherent surface states.

## Contribution

The study identifies coexisting Aharonov–Bohm oscillations and universal conductance fluctuations in TCI nanowires.

## Key findings

- Aharonov–Bohm-type oscillations are observed for Pb1–xSnxTe nanowires with 0.32 ≤ x ≤ 0.51.
- Phase coherence length of 1.4 ± 0.2 μm is measured at 80 mK, indicating ballistic transport on the surface.
- Universal conductance fluctuations suggest diffusive transport in the bulk.

## Abstract

Pb1–x
Sn
x
Te is a topological crystalline insulator (TCI) hosting
topological
surface and hinge states protected by crystal mirror symmetries. The
bulk carrier density can be reduced by tuning the Sn ratio x. Here, we perform low-temperature magnetotransport measurements
on Pb1–x
Sn
x
Te nanowires with varying x values grown by
molecular beam epitaxy. We observe signatures of Aharonov–Bohm
(AB)-type oscillations for 0.32 ≤ x ≤
0.51, which coexist with aperiodic universal conductance fluctuations
(UCFs) and are consistent with phase-coherent transport on the nanowire
surface. We separately analyze the temperature dependence of the AB-type
oscillations and UCFs. The oscillations give a phase coherence length
of l
ϕ = 1.4 ± 0.2 μm
at 80 mK, consistent with the ballistic transport regime. The UCF
provides a significantly smaller l
ϕ, consistent with a diffusive bulk transport channel, parallel to
the ballistic surface. Our results indicate the presence of phase-coherent
surface states on Pb1–x
Sn
x
Te nanowires with 0.32 ≤ x ≤ 0.51.