Tuning Hole Mobility, Concentration, and Repulsion in High-$T_c$ Cuprates via Apical Atoms

TL;DR

This paper develops a first-principles approach to derive effective Hamiltonians for high-$T_c$ cuprates, revealing how apical atom energy influences hole states, mobility, and superconducting properties.

Contribution

It introduces a Wannier-states based method that incorporates Coulomb repulsion to analyze material-specific effects in cuprates, highlighting the role of apical atom $p_z$ states.

Findings

Material dependence mainly from apical atom $p_z$ energy

Modification of Zhang-Rice singlet by triplet states

Implications for $T_c$, gaps, and charge distribution

Abstract

Using a newly developed first-principles Wannier-states approach that takes into account large on-site Coulomb repulsion, we derive the effective low-energy interacting Hamiltonians for several prototypical high-$T_c$ superconducting cuprates. The material dependence is found to originate primarily from the different energy of the apical atom $p_z$ state. Specifically, the general properties of the low-energy hole state, namely the Zhang-Rice singlet, are significantly modified by a triplet state associated with this $p_z$ state, via additional intra-sublattice hoppings, nearest-neighbor "super-repulsion", and other microscopic many-body processes. Possible implications on modulation of $T_c$, local superconducting gaps, charge distribution, hole mobility, electron-phonon interaction, and multi-layer effects are discussed.