Spin-phonon interaction and band effects in the high-T_C superconductor HgBa_2CuO_4

TL;DR

This study investigates how spin-phonon interactions in HgBa_2CuO_4 influence its electronic properties, suggesting a potential role in high-temperature superconductivity, despite their weak quantitative effects.

Contribution

It demonstrates the influence of specific phonon distortions on spin waves and highlights the potential importance of spin-phonon coupling in high-T_C superconductors.

Findings

Stripe-like anti-ferromagnetic spin wave enforced by phonon distortion

Enhanced spin-phonon coupling with shear distortion and Cu–O distance increase

Effects are consistent with observations in high-T_C materials

Abstract

Band calculations show that a stripe-like anti-ferromagnetic spin wave is enforced by a 'half-breathing' phonon distortion within the CuO plane of HgBa_2CuO_4. This spin-phonon coupling is increased further by shear distortion and by increased distance between Cu and apical oxygens. The effects from spin-phonon coupling are consistent with many observations in high-T_C materials. Spin-phonon coupling can be important for the mechanism of spin fluctuations and superconductivity, although the effects are quantitatively weak when using the local density potential.