Nernst response of the Landau tubes in graphite across the quantum limit

TL;DR

This study investigates the Nernst effect in graphite under high magnetic fields, revealing sharp peaks at Landau tube transitions and a significant drop indicating a phase transition and Landau tube destruction beyond the quantum limit.

Contribution

It provides detailed experimental insights into Landau tube behavior and phase transitions in graphite at high magnetic fields up to 45 T.

Findings

Sharp Nernst peaks at Landau tube squeezing

Fixed point at tube flattening

Drastic Nernst drop at phase transition

Abstract

We report on a study of the Nernst effect in graphite extended up to 45 T. The Nernst response sharply peaks each time a Landau tube is squeezed inside the thermally fuzzy Fermi surface and presents a temperature-independent fixed point whenever the tube flattens to a single ring. Beyond the quantum limit, the onset of the field-induced phase transition leads to a drastic drop in the Nernst response signaling the sudden vanishing of Landau tubes. The magnitude of this drop suggests the destruction of multiple Landau tubes possibly as a result of simultaneous nesting of the electron and hole pockets.