Avoided Crossing Phonons Realizes High-Performance Single-Crystalline β-Zn4Sb3 Thermoelectrics
Journal
Advanced Science
ISSN
2198-3844
2198-3844
Date Issued
2024
Author(s)
DOI
10.1002/advs.202411498
Abstract
This study reveals the mechanisms behind the ultralow lattice thermal conductivity κL in β-Zn4Sb3 single crystals through inelastic neutron scattering (INS). Analyzing phonon behaviors and the interaction between acoustic phonons and rattling modes, the first experimental evidence of avoided crossing in β-Zn4Sb3 is provided. The rattler-phonon avoided crossings contribute to the low κL in a β-Zn4Sb3 single crystal, enhancing the thermoelectric figure-of-merit (zT). TEM characterizations of the β-Zn4Sb3 single crystal with intrinsic and ultralow κL reveal a grain-boundary-free structure with uniformly dispersed rotation moiré fringes that contribute to low lattice thermal conductivity while maintaining a uniform elemental distribution. Additionally, the significant impact of crystallinity control coupled with dilute doping on boosting thermoelectric performance, with single-crystalline single leg outperforming their polycrystalline counterparts is demonstrated. Notably, the conversion efficiency η of the undoped β-Zn4Sb3 single leg achieves 1.4% under a temperature gradient of 200 K.
Subjects
avoid crossing phonon
conversion efficiency
moiré fringes
thermoelectrics
β-Zn4Sb3
SDGs
Publisher
Wiley
Type
journal article