Abstract
Materials with simple crystal structure usually exhibit substantial lattice thermal conductivity (κlatt) due to a scarcity of strong phonon-phonon scattering channels. Yet here we find simple CsCl-structure TlBr to have an extremely low room temperature κlatt∼0.5W/m-K, while at low temperature we find a high κlatt of 155W/m-K. This extreme range of conductivity behavior results from lattice-instability-related anharmonicity, effective only at temperatures above ∼30K. Manipulating these instabilities (e.g., pressure, strain) may yield a pathway to ultralow thermal conductivity via intrinsic phonon resistance in similar materials.
| Original language | English |
|---|---|
| Article number | 045403 |
| Journal | Physical Review Materials |
| Volume | 4 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2020 |
Funding
This research was supported by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division and used resources of the Compute and Data Environment for Science (CADES) at Oak Ridge National Laboratory (ORNL).