Experimental electronic structure of the electrically switchable antiferromagnet CuMnAs

TL;DR

This study presents direct ARPES measurements of the electronic structure of tetragonal CuMnAs, revealing the importance of chemical potential control for exploring Dirac fermions in this antiferromagnetic material.

Contribution

First direct ARPES characterization of single-crystalline CuMnAs, aligning experimental data with theoretical predictions after chemical potential correction.

Findings

Excellent agreement between ARPES and DFT after chemical potential correction

Identification of 2x1 surface reconstructions in CuMnAs

Highlighting the need for chemical potential control to access Dirac fermions

Abstract

Tetragonal CuMnAs is a room temperature antiferromagnet with an electrically reorientable N\'eel vector and a Dirac semimetal candidate. Direct measurements of the electronic structure of single-crystalline thin films of tetragonal CuMnAs using angle-resolved photoemission spectroscopy (ARPES) are reported, including Fermi surfaces (FS) and energy-wavevector dispersions. After correcting for a chemical potential shift of $\approx-390$ meV (hole doping), there is excellent agreement of FS, orbital character of bands, and Fermi velocities between the experiment and density functional theory calculations. Additionally, 2x1 surface reconstructions are found in the low energy electron diffraction (LEED) and ARPES. This work underscores the need to control the chemical potential in tetragonal CuMnAs to enable the exploration and exploitation of the Dirac fermions with tunable masses, which are predicted to be above the chemical potential in the present samples.