Two-carrier analyses of the transport properties of black phosphorus under pressure

TL;DR

This study investigates black phosphorus's electronic transport under pressure, revealing a transition from semiconducting to semimetallic behavior with high mobility carriers and large magnetoresistance, challenging conventional models.

Contribution

It provides a detailed analysis of pressure-induced electronic phase transition in black phosphorus using a two-carrier model and quantum oscillations.

Findings

Coexistence of two hole types at low pressure

Nearly compensated electron-hole carriers at high pressure

High mobility electrons with sign inversion in Hall resistivity

Abstract

We report on the electronic transport properties of black phosphorus and analyze them using a two-carrier model in a wide range of pressure up to 2.5 GPa. In semiconducting state at 0.29 GPa, the remarkable non-linear behavior in the Hall resistance is reasonably reproduced by assuming the coexistence of two kinds of hole with different densities and mobilities. On the other hand, two-carrier analyses of the magnetotransport properties above 1.01 GPa suggest the coexistence of high mobility electron and hole carriers that have almost the same densities, i.e., nearly compensated semimetallic nature of black phosphorus. In the semimetallic state, analyses of both the two-carrier model and quantum oscillations indicate a systematic increase in the carrier densities as pressure increases. An observed sign inversion of Hall resistivity at low magnetic fields suggests the existence of high mobility electrons (\sim105 cm2 V-1 s-1) that is roughly ten times larger than that of holes, in the semimetallic black phosphorus. We conclude that the extremely large positive magnetoresistance that has been observed in semimetallic state cannot be reproduced by a conventional two-carrier model.