Thermoelectric response in the incoherent transport region near Mott transition: the case study of La1-xSrxVO3

TL;DR

This study investigates high-temperature thermoelectric behavior near the Mott transition in La1-xSrxVO3, revealing that thermopower reflects entropy per charge carrier and confirming Heikes formula applicability in correlated systems.

Contribution

It demonstrates the validity of Heikes formula for thermopower in real correlated electron systems at practical temperatures near the Mott transition.

Findings

Thermopower approaches Heikes limit values at high temperatures.

Incoherent charge transport dominates near the Mott transition.

Thermopower correlates with entropy per charge carrier.

Abstract

We report a systematic investigation on the high-temperature thermoelectric response in a typical filling-control Mott transition system La1-xSrxVO3. In the vicinity of the Mott transition, incoherent charge transport appears with increasing temperature and the thermopower undergoes two essential crossovers, asymptotically approaching the limit values expected from the entropy consideration, as known as Heikes formula. By comparison with the results of the dynamical mean field theory, we show that the thermopower in the Mott critical state mainly measures the entropy per charge carrier that depends on electronic degrees of freedom available at the measurement temperature. Our findings verify that the Heikes formula is indeed applicable to the real correlated electron systems at practical temperatures (T>200K).