We study the atomic collapse phenomenon in K and K′ valley of gapped graphene. Bound states induced by Coulomb impurity in the gap turn into atomic collapse resonances as the charge increases beyond the supercritical charge Zc. Zc increases sublinear with the band gap Δ. The atomic collapse resonances result in peaks in the LDOS at the same energies in K and K′ valley, but the strong (weak) LDOS peaks in K valley are weak (strong) LDOS peaks in K′ valley reminiscent of pseudospin polarization phenomenon. From a spatial LDOS analysis of the atomic collapse resonance states, we assign specific atomic orbitals to the atomic collapse resonances. Remarkably, the two p atomic orbital atomic collapse states are no longer degenerate and splits into two having lobes in different directions in the graphene plane.
Cite
@article{arxiv.2501.15049,
title = {Atomic collapse in gapped graphene: lattice and valley effects},
author = {Jing Wang and Xiaotai Wu and Wen-Sheng Zhao and Yuhua Cheng and Yue Hu and Francois M. Peeters},
journal= {arXiv preprint arXiv:2501.15049},
year = {2025}
}