Ab initio study of anomalous temperature dependence of resistivity in V-Al alloys

TL;DR

This study uses ab initio calculations combining the Kubo-Greenwood formalism and CPA to explain the anomalous negative temperature coefficient of resistivity in V-Al alloys, matching experimental Mooij correlation.

Contribution

It provides a quantitative ab initio explanation for the Mooij correlation in V-Al alloys, identifying non-Boltzmann contributions to resistivity behavior.

Findings

Reproduces the Mooij correlation in V-Al alloys

Identifies non-Boltzmann contributions to resistivity

Matches experimental temperature dependence of conductivity

Abstract

V$_{1-x}$Al$_x$ is a representative example of highly resistive metallic alloys exhibiting a crossover to a negative temperature coefficient of resistivity (TCR), known as the Mooij correlation. Despite numerous proposals to explain this anomalous behavior,none have provided a satisfactory quantitative explanation thus far. In this work, we calculate the electrical conductivity using an ab initio methodology that combines the Kubo-Greenwood formalism with the coherent potential approximation (CPA). The temperature dependence of the conductivity is obtained within a CPA-based model of thermal atomic vibrations. Using this approach, we observe the crossover to the negative TCR behavior in V$_{1-x}$Al$_x$, with the temperature coefficient following the Mooij correlation, which matches experimental observations in the intermediate-to-high temperature range. Analysis of the results allows us to clearly identify a non-Boltzmann contribution responsible for this behavior and describe it as a function of temperature and composition.