Thermoelectric transport across the metamagnetic transition of CeRu2Si2

TL;DR

This study investigates how thermoelectric properties of CeRu2Si2 change across its metamagnetic transition, revealing a significant thermopower enhancement and Fermi surface deformation driven by magnetic field-induced topological changes.

Contribution

It provides the first detailed thermopower measurements across the metamagnetic transition in CeRu2Si2 at very low temperatures, linking thermoelectric behavior to Fermi surface topology changes.

Findings

Large negative thermopower enhancement at transition

Sudden slope change in thermopower with field

Discrepancy between thermodynamic and transport responses

Abstract

We have measured the thermopower across the metamagnetic transition of the heavy fermion compound CeRu2Si2 at temperatures down to 0.1K and magnetic fields up to 11.5T. We find a large negative enhancement of the thermopower on crossing the metamagnetic field, as well as a sudden change in slope. We argue that this is consistent with the Zeeman-driven deformation of the Fermi surface through a topological transition. The field dependence of the thermopower highlights the discrepancy between thermodynamic and transport properties across the metamagnetic transition.