Half-metallic to ferromagnetic phase transition in CrSH monolayer using DFT+U and BO-MD calculations

TL;DR

This study uses advanced computational methods to analyze CrSH monolayers, revealing a phase transition from half-metallic to ferromagnetic states, with implications for spintronic applications.

Contribution

It provides a detailed DFT+U and BO-MD analysis of CrSH monolayers, identifying phase stability and transition mechanisms between 1T and 2H phases.

Findings

1T-CrSH is stable and semiconducting with a 1.1 eV band gap.

2H-CrSH is a metastable half-metallic phase.

Phase transition occurs at 300 K from 2H to 1T phase.

Abstract

We present a comprehensive investigation of the structural, electronic, magnetic, and vibrational properties of CrSH monolayers in the 1T and 2H phases using density functional theory (DFT)+U calculations with a converged Hubbard U value of 5.54 eV and Born-Oppenheimer molecular dynamics (BO-MD) simulations. The ferromagnetic (FM) 1T-CrSH phase is found to be dynamically and thermodynamically stable, exhibiting semiconducting behavior with a band gap of 1.1 eV and a magnetic moment of 3.0 $\mu$B per Cr atom. On the other hand, the 2H-CrSH phase is a half-metallic (HM) phase. We found that it is a metastable phase and undergoes a rapid phase transition to the 1T phase under finite temperature at 300 K. Phonon calculations, performed using the finite displacement method and corrected for rotational invariance corrections with Huang and Born-Huang sum rules, resolve spurious imaginary frequencies in the flexural ZA phonon mode near the $\Gamma$-point, ensuring physical accuracy. These findings establish CrSH monolayers as promising candidates for spintronic and valleytronic applications, with tunable electronic properties enabled by phase engineering.