# Low temperature features in the heat capacity of unary metals and intermetallics for the example of bulk aluminum and Al$_3$Sc

## TL;DR

This study combines experimental calorimetry and advanced density functional theory calculations to analyze low-temperature heat capacity features in aluminum and Al3Sc, revealing the roles of vibrational and electronic effects and the impact of scandium addition.

## Contribution

It demonstrates that semilocal exchange correlation functionals can accurately capture low-temperature heat capacity features, including electron-phonon coupling, in aluminum and Al3Sc.

## Key findings

- Accurate description of heat capacity features below 50 K
- Identification of deviations from Debye behaviour
- Reduction of low-temperature features with Sc addition

## Abstract

We explore the competition and coupling of vibrational and electronic contributions to the heat capacity of Al and Al$_3$Sc at temperatures below 50 K combining experimental calorimetry with highly converged finite temperature density functional theory calculations. We find that semilocal exchange correlation functionals accurately describe the rich feature set observed for these temperatures, including electron-phonon coupling. Using different representations of the heat capacity, we are therefore able to identify and explain deviations from the Debye behaviour in the low-temperature limit and in the temperature regime 30 - 50 K as well as the reduction of these features due to the addition of Sc.