Thermoelectric Power of the YbT$_{2}$Zn$_{20}$ (T = Fe, Ru, Os, Ir, Rh, and Co) Heavy Fermions

TL;DR

This study measures the thermoelectric power of YbT$_{2}$Zn$_{20}$ heavy fermions to understand their electronic correlations, revealing characteristic minima, temperature dependencies, and correlations with specific heat data.

Contribution

It provides new insights into the thermoelectric behavior and energy scales of YbT$_{2}$Zn$_{20}$ heavy fermions, linking thermoelectric power to electronic correlations.

Findings

Large negative local minimum in $S(T)$ around -70 μV/K

Linear $S(T)$ at low temperatures with enhanced slope

Strong correlation between thermoelectric and specific heat properties

Abstract

The thermoelectric power, $S(T)$, of the heavy fermions YbT$_{2}$Zn$_{20}$ ($T$ = Fe, Ru, Os, Ir, Rh, and Co) has been measured to characterize their strong electronic correlations. A large, negative, local minimum in $S(T)$ with approximately -70 $\mu$V/K is found for all compounds. From the observed local minimum, the energy scales associated with both the Kondo temperature and the crystalline electric field splitting are deduced and compared to previous specific heat measurements. At low temperatures, $S(T)$ follows a linear temperature dependence, $S(T)$ = $\alpha T$, with an enhanced value of $\alpha$ which is characteristic for a heavy fermion state. In the zero temperature limit, the enhanced $\alpha$ value strongly correlates with the electronic specific heat coefficient, $C(T)/T$, due to the large density of states at the Fermi level.