Tunable quantum interference effect on magnetoconductivity in few-layer black phosphorus

TL;DR

This paper develops a comprehensive theory of quantum interference effects in few-layer black phosphorus, revealing tunable magnetoconductivity behaviors across different electronic phases with anisotropic considerations.

Contribution

It introduces a novel anisotropic weak localization/antilocalization theory and applies it to predict quantum interference effects in various phases of black phosphorus.

Findings

Crossover from weak localization to antilocalization in BP.

Nontrivial power-law dependence of magnetoconductivity at the semi-Dirac transition.

Magnetoconductivity to Boltzmann conductivity ratio is direction-independent.

Abstract

In this study, we develop a systematic weak localization/antilocalization theory fully considering the anisotropy and Berry phase of the system, and apply it to various phases of few-layer black phosphorus (BP), which has a highly anisotropic electronic structure with an electronic gap size tunable even to a negative value. The derivation of a Cooperon ansatz for the Bethe-Salpeter equation in a general anisotropic system is presented, revealing the existence of various quantum interference effects in different phases of few-layer BP, including a crossover from weak localization to antilocalization. We also predict that the magnetoconductivity at the semi-Dirac transition point will exhibit a nontrivial power-law dependence on the magnetic field, while following the conventional logarithmic field-dependence of 2D systems in the insulator and Dirac semimetal phases. Notably, the ratio between the magnetoconductivity and Boltzmann conductivity turns out to be independent of the direction, even in strongly anisotropic systems. Finally, we discuss the tunability of the quantum corrections of few-layer BP in terms of the symmetry class of the system.