Oscillating Nernst-Ettingshausen effect in Bismuth across the quantum limit

TL;DR

This paper investigates the oscillating Nernst-Ettingshausen effect in Bismuth under high magnetic fields, revealing sharp peaks in thermoelectric coefficients at the quantum limit, consistent with edge excitation theories.

Contribution

It presents the first experimental study of thermoelectric effects in Bismuth at the quantum limit, highlighting oscillations and peaks in thermoelectric coefficients linked to Landau level crossings.

Findings

Oscillating thermoelectric response larger than background

Sharp peaks in Nernst and Ettingshausen coefficients at Landau level crossing

Temperature-independent maximum of the Ettingshausen coefficient

Abstract

In elemental Bismuth, 10$^5$ atoms share a single itinerant electron. Therefore, a moderate magnetic field can confine electrons to the lowest Landau level. We report on the first study of metallic thermoelectricity in this regime. The main thermoelectric response is off-diagonal with an oscillating component several times larger than the non-oscillating background. When the first Landau level attains the Fermi Energy, both the Nernst and the Ettingshausen coefficients sharply peak, and the latter attains a temperature-independent maximum. A qualitative agreement with a theory invoking current-carrying edge excitations is observed.