Testing a New Meta-GGA Functional in Cuprates: The Case of La₂CuO₄.

Lanthanum Copper Oxide (La₂CuO₄, or LCO) is a material known to have applications in high-temperature superconductivity. Using density functional theory (DFT), LCO’s ground state properties can be understood. While previous studies have been performed on LCO using both generalized gradient approximation (GGA) and meta-GGA functionals such as PBE, SCAN and r²SCAN, we use the recently developed Lebeda-Aschebrock-Kümmel (LAK) density functional in order to test its performance with cuprates and to benchmark against previous studies and experimental data. In this investigation, we analyze three different phases (low-temperature orthorhombic (LTO), low-temperature tetragonal (LTT), and high-temperature tetragonal (HTT)) of LCO. Specifically, properties studied include lattice parameters, band gap, magnetism, density of states, and band structure. All simulations were run through the National Energy Research Scientific Computing Center (NERSC) using the Vienna Ab Initio Simulation Package (VASP), and outputs were processed using VESTA and Python scripts. From the data collected, we concluded that LCO’s ground state structure is the antiferromagnetic LTO lattice phase. Additionally, LAK yielded very accurate results for LCO’s electronic properties, but it overestimated the lattice parameters. This insight provides a path for further research into improving LAK’s performance and into the study of other cuprates.