Dephasing in strongly anisotropic black phosphorus

TL;DR

This study investigates weak localization and dephasing in black phosphorus, revealing anisotropic effects and a unique temperature dependence of the dephasing length related to its crystal structure.

Contribution

It provides the first detailed analysis of weak localization and dephasing in black phosphorus, highlighting anisotropic effects and deviations from typical 2D electron-electron scattering behavior.

Findings

Dephasing length $L_\phi$ reaches 55 nm at high hole density

$L_\phi$ decreases weakly with temperature above 1 K

Weak localization fits the Hikami-Larkin-Nagaoka model

Abstract

Weak localization was observed and determined in a black phosphorus (bP) field-effect transistor 65 nm thick. The weak localization behaviour was found to be in excellent agreement with the Hikami-Larkin-Nagaoka model for fields up to 1~T, from which characteristic scattering lengths could be inferred. The dephasing length $L_\phi$ was found to increase linearly with increasing hole density attaining a maximum value of 55 nm at a hole density of approximately $10^{13} cm^{-2}$ inferred from the Hall effect. The temperature dependence of $L_\phi$ was also investigated and above 1~K, it was found to decrease weaker than the $L_\phi \propto T^{-\frac{1}{2}}$ dependence characteristic of electron-electron scattering in the presence of elastic scattering in two dimensions. Rather, the observed power law was found to be close to that observed previously in other quasi-one-dimensional systems such as metallic nanowires and carbon nanotubes. We attribute our result to the crystal structure of bP which host a `puckered' honeycomb lattice forming a strongly anisotropic medium