A van Hove singularity (VHS) often significantly amplifies the electronic instability of a crystalline solid, including correlation-induced phenomena such as Hund's metallicity. We perform a systematic study on the interplay between Hund's coupling and electronic structures with a VHS focusing on Hund's metallicity. We construct a simplified tight-binding model targeting cubic perovskite materials and test the effects of the VHS utilizing dynamical mean-field theory with an exact diagonalization solver. The quasiparticle weight and the low-frequency power exponent of the self-energy provide a quantitative estimation of metallicity over the phase diagram. We find the VHS to substantially enhance Hund's metallicity. The results here suggest a range of parameters through which a VHS can bring great synergy with Hund's coupling.
@article{arxiv.2107.05906,
title = {Hund's metallicity enhanced by van Hove singularity in cubic perovskite systems},
author = {Hyeong Jun Lee and Choong H. Kim and Ara Go},
journal= {arXiv preprint arXiv:2107.05906},
year = {2021}
}