Effects of spin-phonon interaction on the properties of in high-T$_C$ superconductors

TL;DR

This paper investigates how spin-phonon interactions influence the electronic properties of high-Tc superconductors, revealing their role in pseudogap formation and other normal state phenomena through band calculations.

Contribution

It provides a detailed band-structure analysis showing the interplay between phonons and spin waves in high-Tc cuprates, highlighting their impact on pseudogaps and superconductivity.

Findings

Phonons favor spin waves and vice versa.

Pseudogaps naturally emerge in striped materials with strong SPC.

Results align with experimental observations of lattice and magnetic effects.

Abstract

The mechanism of spin-phonon coupling in high-T$_C$ copper oxides is explored from band calculations on La$_{(2-x)}$Sr$_x$CuO$_4$ and HgBa$_2$CuO$_4$ systems. The LMTO band calculations, based on the local density approximation, are made for cells containing frozen phonon displacements and/or spin waves within the CuO plane. The virtual crystal approximation is used for studies of hole doped systems. The main result is that phonons are favorable for spin waves and vice-versa, and that pseudogaps appear naturally in the band structures of striped materials with strong SPC. The qualitative results are compatible with many observations showing that the properties of high-T$_C$ superconductors depend both on lattice interactions and magnetic fluctuations. The band results are used to model various properties, mainly of the normal state, such as isotope effects, pseudogaps, Fermi surface broadening, T-dependence of the pseudogap, phonon softening and some aspects of superconductivity. The possibility of perpendicular SPC is investigated, partly by the use of a nearly free electron model.