Theory of temperature dependence of the Fermi surface-induced splitting of the alloy diffuse-scattering intensity peak

TL;DR

This paper explains the temperature-dependent splitting of diffuse scattering peaks in Cu3Au alloy by analyzing the wavevector and temperature dependence of the self-energy, proposing two calculation methods that align with experimental observations.

Contribution

It introduces two novel approaches for calculating the self-energy to explain temperature effects on diffuse scattering in alloys.

Findings

Self-energy dependence explains peak splitting behavior.

Both methods predict increased splitting with temperature.

Results agree with experimental data.

Abstract

The explanation is presented for the temperature dependence of the fourfold intensity peak splitting found recently in diffuse scattering from the disordered Cu3Au alloy. The wavevector and temperature dependence of the self-energy is identified as the origin of the observed behaviour. Two approaches for the calculation of the self-energy, the high-temperature expansion and the alpha-expansion, are proposed. Applied to the Cu3Au alloy, both methods predict the increase of the splitting with temperature, in agreement with the experimental results.