Magneto-transport properties of tellurium under extreme conditions

TL;DR

This paper explores how pressure and magnetic fields influence tellurium's electrical and structural properties, revealing superconductivity, metallic surface states, and magnetoresistance effects under extreme conditions.

Contribution

It provides new insights into tellurium's phase transitions, surface states, and transport properties under high pressure and magnetic fields, challenging previous assumptions.

Findings

Resistivity decreases with pressure but remains semiconducting up to 4 GPa.

Superconductivity appears at 2 K in the metallic phase above 4 GPa.

Metallic surface states are present on as-cleaved tellurium surfaces.

Abstract

This study investigates the transport properties of a chiral elemental semiconductor tellurium (Te) under magnetic fields and pressure. Application of hydrostatic pressure reduces the resistivity of Te, while its temperature dependence remains semiconducting up to 4 GPa, contrary to recent theoretical and experimental studies. Application of higher pressure causes structural as well as semiconductor--metal transitions. The resulting metallic phase above 4 GPa exhibits superconductivity at 2 K along with a noticeable linear magnetoresistance effect. On the other hand, at ambient pressure, we identified metallic surface states on the as-cleaved (10$\bar{1}$0) surfaces of Te. The nature of these metallic surface states has been systematically studied by analyzing quantum oscillations observed in high magnetic fields. We clarify that a well-defined metallic surface state exists not only on chemically etched samples that were previously reported, but also on as-cleaved ones.