Nanoscale Determination of the Mass Enhancement Factor in the Lightly-Doped Bulk Insulator Lead Selenide

TL;DR

This paper introduces a novel Landau level spectroscopy method to directly measure the Eliashberg function in lightly-doped PbSe, enabling nanoscale investigation of electron-phonon interactions relevant to thermoelectric properties.

Contribution

The study develops a new experimental approach to extract the Eliashberg function at the nanoscale, advancing understanding of electron-phonon coupling in thermoelectric materials.

Findings

Successful application to lightly-doped PbSe

High energy resolution limited by thermal broadening

Potential to detect nanoscale variations in mass enhancement

Abstract

Bismuth chalcogenides and lead telluride/selenide alloys exhibit exceptional thermoelectric properties which could be harnessed for power generation and device applications. Since phonons play a significant role in achieving these desired properties, quantifying the interaction between phonons and electrons, which is encoded in the Eliashberg function of a material, is of immense importance. However, its precise extraction has in part been limited due to the lack of local experimental probes. Here we construct a method to directly extract the Eliashberg function using Landau level spectroscopy, and demonstrate its applicability to lightly-doped thermoelectric bulk insulator PbSe. In addition to its high energy resolution only limited by thermal broadening, this novel experimental method could be used to detect variations in mass enhancement factor at the nanoscale. As such, it opens up a new pathway for investigating the effects of chemical defects, surface doping and strain on the mass enhancement factor.