Impact Factor:2.8

DOI number:10.1088/1367-2630/ae6bb0

Affiliation of Author(s):中国矿业大学

Journal:New Journal of Physics

Place of Publication:Institute of Physics (IOP)

Funded by:国家自然科学基金面上项目(No. 12374079)

Key Words:lone-pair electrons, phonon coherence, anharmonicity

Abstract:Conventional Peierls theory is inadequate for describing thermal transport in strongly anharmonic compounds, such as two-dimensional layered chalcogenides containing lone-pair electrons; the underlying physics of their ultralow thermal conductivity remains to be explored. Here, using monolayer Sb2Te3 as a model system, we elucidate the mechanism behind its ultralow lattice thermal conductivity by evaluating the competing contributions of particle-like propagation and wave-like tunneling. The particle-like transport channel is suppressed by the dominant quartic anharmonicity induced by the stereochemically active lone-pair electrons of the tetrahedrally coordinated Te(1)-5pz orbital, primarily via enhancement of four-phonon scattering. In contrast, the wave-like transport channel is enhanced by the flattening of the Te(2)-derived phonon branches, a result of the relatively weak covalent bonding in the octahedral coordination, thereby promoting phonon coherence. Consequently, the combined model of the Te(1)-dominated particle-like and Te(2)-dominated wave-like channels accurately accounts for the total thermal conductivity, achieving excellent agreement with experimental measurements in both magnitude and temperature dependence. For example, the calculated T−0.73 scaling exponent for the temperature dependence closely matches the experimental value of T−0.76. Our work identifies the interplay of lone-pair electrons and covalent bonding configuration as a key governing mechanism for thermal transport in two-dimensional layered chalcogenides, providing a novel perspective on their thermal properties.

First Author:吴凯

Co-author:周冉,时洪亮

Indexed by:Journal paper

Correspondence Author:段益峰*

Document Code:053504

Discipline:Natural Science

First-Level Discipline:Physics

Document Type:J

Volume:28

Page Number:053504

ISSN No.:1367-2630

Translation or Not:no

Date of Publication:2026-05-21

Included Journals:SCI

Links to published journals:https://iopscience.iop.org/article/10.1088/1367-2630/ae6bb0