2024/12/23 by Ian A. Leahy, Leahy, Ian, Andrew C. Treglia +6 · 1 citation
Engineering · Materials Science · #FOS: Physical sciences #Intermetallics and Advanced Alloy Properties #Materials Science (cond-mat.mtrl-sci) #Metallurgical and Alloy Processes #Strongly Correlated Electrons (cond-mat.str-el) #Thermodynamic and Structural Properties of Metals and Alloys
paper · pdf · doi:10.48550/arxiv.2412.17688
openalex publication_date 2024/12/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In studying compensated semimetals, the two-band model has proven extremely useful in capturing electrical conductivity under magnetic field, as a function of density and mobility of electron-like and hole-like carriers. However, it rarely offers practical insight into magneto-thermoelectric properties. Here, we report the field dependence of thermoelectric (TE) coefficients in a highly compensated semimetal NbSb2, where we find the Seebeck and Nernst coefficients increase quadratically and linearly with applied magnetic field, respectively. Such field dependence was predicted in previous work that studied a system of two parabolic bands, within semiclassical Boltzmann transport theory when the following two conditions are simultaneously met:ωcτ≫ 1 and tanθH ≪ 1. Under these conditions, we find the field dependence of the TE coefficients directly provides a relation between the electron-like (ne) and hole-like (nh) carrier densities, which in turn can be used to refine two-band model fitting. With this, we find the compensation factor ((|Δn|)/(ne)) of NbSb2 is two orders of magnitude smaller than what was found in unrestricted fitting, resulting in a larger saturation field scale for magnetoresistance. Within the same framework of the semiclassical theory, we also deduce that the thermoelectric Hall angle tanθγ = \fracSxySxx can be expressed as ((|Δn|)/(ne) × ωcτ)-1, which serves as a parameter to predict the degree of compensation. Our findings offer crucial insights into identifying empirical conditions for field-induced enhancement of TE performance and into engineering efficient thermoelectric devices based on semimetallic materials.