Abstract
Dislocations in van der Waals (vdW) layered nanomaterials induce strain and structural changes that substantially impact thermal transport. Understanding these effects could enable the manipulation of dislocations for improved thermoelectric and optoelectronic applications, but experimental insights remain limited. In this study, we use synthetic Eshelby twisted vdW GeS nanowires (NWs) with single screw dislocations as a model system to explore the interplay between dislocation-induced structural modifications and lattice thermal conductivity. Our measurements reveal a monoclinic structure stabilized by the dislocation, leading to a substantial drop in thermal conductivity for larger-diameter NWs (70% at room temperature), supported by first-principles calculations. Interestingly, we also find an anomalous enhancement of thermal conductivity with decreasing diameter in twisted NWs, contrary to typical trends in non-twisted GeS NWs. This is attributed to increased conductivity near the NW cores due to compressive strain around the central dislocations, and aligns with a density-functional-theory-informed core–shell model. Our results highlight the critical role of dislocations in thermal conduction, providing fundamental insights for defect and strain engineering in advanced thermal applications.
| Original language | English |
|---|---|
| Article number | 2391 |
| Pages (from-to) | 728-734 |
| Number of pages | 7 |
| Journal | Nature Materials |
| Volume | 24 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2025 |
Funding
This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under contract DE-AC02-05CH11231 (Organic–Inorganic Nanocomposites KC3104). Thermal conductivity measurements and theoretical analysis of the strain induced structure change were supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under contract DE-AC02-05CH11231 (EMAT programme KC1201). Y.L. and Y.W. were supported by the National Science Foundation under award DMR-2340751. R.C. and J.Y. acknowledge the support from the Heising–Simons Faculty Fellowship. Y.Y. and Y.S. acknowledge support from the National Science Foundation award DMR-2145455. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, US Department of Energy, under contract DE-AC02-05CH11231. This work was performed, in part, at the Center for Nanoscale Materials, a US Department of Energy Office of Science User Facility, and supported by the US Department of Energy, Office of Science, under contract DE-AC02-06CH11357. Calculations and manuscript development (L.L.) were supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Material Sciences and Engineering Division. The calculations used resources of the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the US Department of Energy under contract DE-AC05-00OR22725, and resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the US Department of Energy under contract DE-AC02-05CH11231. We thank J. Wen at Argonne National Laboratory and N. Tamura at Lawrence Berkeley National Laboratory for assistance with the material characterization as well as Z. Fang for the NW synthesis.