Work

Enhanced Energy Dependence of Carrier Density of States, Relaxation Time, and Group Velocity in Highly Asymmetric Bands Yields Large Seebeck Coefficients

Year: 2025

Type: article

Abstract: Thermoelectric materials ‌enable efficient conversion‌ between thermal and electric energy, ‌emerging as eco-friendly options‌ for power generation. Traditionally, ‌gapless systems‌ have received limited attention regarding their thermoelectric performance due to very small Seebeck coefficients. However, by using first-principles calculations and Boltzmann transport theory, we demonstrated that the semimetallic InAs and InSb compounds are exceptions. They exhibit strong band asymmetry, which is different from metallic InBi and significantly enhances the energy dependence of their carrier density of states, relaxation time, and group velocity. Such characteristics lead to these systems showing large intrinsic Seebeck coefficients without doping or strain. Combined with their low lattice thermal conductivity, the room-temperature ZT values of InAs reach 1.1 and 1.0, respectively. Further electron-phonon coupling calculations reveal that InAs and InSb maintain a high Seebeck coefficient even with refined conductivities. The interplay between high-mobility electrons and valence-band scattering underpins this performance. Our work redefines semimetals as a promising class of thermoelectric materials, bridging the gap between conventional semiconductors and gapless systems for energy applications.

Source: Journal of Physics Condensed Matter

DOI: 10.1088/1361-648x/ae06e3

Authors: Shihao Han, bing lv, Qinghang Tang, Weixiang Kong

Institution: Guizhou Normal University

Language: English

Topic: Advanced Thermoelectric Materials and Devices

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $3,325