Aharonov-Bohm oscillations in phosphorene quantum rings: mass anisotropy compensation by confinement potential

TL;DR

This paper studies how elliptic deformation of phosphorene quantum rings can compensate for mass anisotropy effects, restoring Aharonov-Bohm oscillations and revealing conditions for isotropic-like spectra.

Contribution

It demonstrates that elliptic deformation can counteract phosphorene's mass anisotropy, enabling AB oscillations and spectrum symmetry similar to isotropic rings.

Findings

Elliptic deformation restores AB oscillations in phosphorene rings.

A specific semi-axes ratio makes the spectrum identical to isotropic rings.

Identifies a generalized angular momentum operator that simplifies energy level analysis.

Abstract

We consider the Aharonov-Bohm (AB) effect on a confined electron ground state in a quantum ring defined electrostatically within the phosphorene monolayer. The strong anisotropy of effective masses in phosphorene quenches ground-state oscillations for a circular ring because of interrupted persistent current circulation around the ring. An elliptic deformation of the confinement potential can compensate for the anisotropy of the effective masses and produce ground-state parity transformations with the AB periodicity. Moreover, a specific ratio of the semiaxes is determined for which the spectrum becomes identical to that of a circular quantum ring and an isotropic effective mass. We identify a generalized angular momentum operator which commutes with the continuum Hamiltonian for the chosen ratio of the semi-axes that closes the avoided crossings of energy levels for states of the same parity and spin. Ground-state oscillations for the two-electron ground state are also discussed.