# Anomalous specific heat peak of BaVS$_3$ at 69 K explained by enhanced electron scattering upon ion relocation

## TL;DR

This paper explains the anomalous heat capacity peak at 69 K in BaVS$_3$ as resulting from increased electron scattering due to structural reorientation during a phase transition, aligning with experimental observations.

## Contribution

It provides a quantitative model linking structural transition to enhanced electron scattering and the resulting heat capacity anomaly in BaVS$_3$.

## Key findings

- The heat capacity peak is sample dependent and broad.
- Enhanced electron scattering accounts for the entropy increase.
- The model accurately reproduces the heat capacity and conductivity features.

## Abstract

The present study deals with the anomalous heat capacity peak and thermal conductivity of BaVS$_3$ near the metal-insulator transition present at $69$ K. The transition is related to a structural transition from an orthorhombic to monoclinic phase. Heat capacity measurements at this temperature exhibit a significant and relatively broad peak, which is also sample dependent. The present study calculates the entropy increase during the structural transition and we show that the additional entropy is caused by enhanced electron scattering as a result of the structural reorientation of the nuclei. Within the model it is possible to explain quantitatively the observed peak alike structure in the heat capacity and in heat conductivity.