Work

Highly dispersive electron relaxation and colossal thermoelectricity in the correlated semiconductor FeSb 2

Year: 2013

Type: article

Abstract: We show that the colossal thermoelectric power $S(T)$ observed in the correlated semiconductor FeSb${}_{2}$ below 30 K is accompanied by a huge Nernst coefficient $\ensuremath{\nu}(T)$ and magnetoresistance MR$(T)$. Markedly, the latter two quantities are enhanced in a strikingly similar manner. While in the same temperature range, $S(T)$ of the reference compound FeAs${}_{2}$, which has a seven-times-larger energy gap, amounts to nearly half of that of FeSb${}_{2}$, its $\ensuremath{\nu}(T)$ and MR$(T)$ are intrinsically different to FeSb${}_{2}$: They are smaller by two orders of magnitude and have no common features. Underlying the essentially different thermoelectric properties between FeSb${}_{2}$ and FeAs${}_{2}$, a large mismatch between the electrical and thermal Hall mobilities is found only in the former compound. With the charge transport of FeAs${}_{2}$ successfully captured by the density functional theory, we emphasize a significantly dispersive electron-relaxation time $\ensuremath{\tau}({\ensuremath{\epsilon}}_{k})$ related to electron-electron correlations to be at the heart of the peculiar thermoelectricity and magnetoresistance of FeSb${}_{2}$.

Source: Physical Review B

DOI: 10.1103/physrevb.88.245203