Heat Capacity study of $\beta$-FeSi$_2$ single crystals

TL;DR

This study measures the heat capacity of $eta$-FeSi$_2$ single crystals, revealing anomalies at specific temperatures that suggest a transition from single to multiple carrier systems, supporting previous resistivity findings.

Contribution

First heat capacity measurements of $eta$-FeSi$_2$ single crystals that identify anomalies indicating electronic transitions.

Findings

Anomalies at ~160 K and ~255 K in heat capacity data.

Evidence for a transition from single to multiple carrier systems around 220 K.

Corroborates previous resistivity and thermoelectric effect results.

Abstract

Heat Capacity of needle-like [length=5mm, diameter=1 mm] $\beta$-FeSi$_{2}$ single crystal, grown by chemical vapor transport has been measured. Two anomalies are found, a broad deviation centered around 160 K and a clear deviation at a temperature of 255 K approximately. We have attempted to relate these to the anomalies previously reported in the case of the resistivity data. The Transient Thermoelectric Effect [TTE] results lead us to the inference that the system under goes from single carrier system to at least two carrier system at 220 K-our heat capacity results seem to provide further independent evidence for this transition in this system.