Particle-hole symmetry breaking in the pseudogap state of Pb0.55Bi1.5Sr1.6La0.4CuO6+d: A quantum-chemical perspective

TL;DR

This study uses quantum-chemical methods on Bi2201 systems to show how a second O2pc character band influences particle-hole symmetry breaking in the pseudogap state, supporting a two-band mechanism for high-Tc superconductivity.

Contribution

It demonstrates how local crystal field effects can induce a second O2pc band crossing the Fermi level, explaining particle-hole symmetry breaking in cuprates.

Findings

Identification of a second O2pc band crossing the Fermi level.

Explanation of particle-hole symmetry breaking in the pseudogap.

Support for a two-bands-on-a-checkerboard mechanism in high-Tc superconductivity.

Abstract

Two Bi2201 model systems are employed to demonstrate how, beside the Cu-O \sigma-band, a second band of purely O2p\pi character can be made to cross the Fermi level owing to its sensitivity to the local crystal field. This result is employed to explain the particle-hole symmetry breaking across the pseudo-gap recently reported by Shen and co-workers, see M. Hashimoto et al., Nature Physics 6, (2010) 414. Support for a two-bands-on-a-checkerboard candidate mechanism for High-Tc superconductivity is claimed.