# Strongly Tunable Anisotropic Thermal Transport in MoS2 by Strain and Lithium Intercalation: First--Principles Calculations

## TL;DR

This study uses first-principles calculations to demonstrate that lithium intercalation and strain can reversibly and significantly tune the anisotropic thermal conductivity of MoS2, enabling advanced heat management and phononic device design.

## Contribution

It reveals the large, reversible tunability of MoS2's thermal conductivity anisotropy through combined strain and lithium intercalation, a novel approach for thermal control.

## Key findings

- Thermal conductivity can be tuned over one to two orders of magnitude.
- Thermal conductivity anisotropy can be modulated by two orders of magnitude.
- Both in-plane and cross-plane conductivities are highly sensitive to strain and intercalation.

## Abstract

The possibility of tuning the vibrational properties and the thermal conductivity of layered van der Waals materials either chemically or mechanically paves the way to significant advances in nanoscale heat management. Using first-principles calculations we investigate the modulation of heat transport in MoS2 by lithium intercalation and cross-plane strain. We find that both the in-plane and cross-plane thermal conductivity (kr, kz) of MoS2 are extremely sensitive to both strain and electrochemical intercalation. Combining lithium intercalation and strain, the in-plane and cross-plane thermal conductivity can be tuned over one and two orders of magnitude, respectively. Furthermore, since kr and kz respond in different ways to intercalation and strain, the thermal conductivity anisotropy can be modulated by two orders of magnitude. The underlying mechanisms for such large tunability of the anisotropic thermal conductivity of \Mos are explored by computing and analyzing the dispersion relations, group velocities, relaxation times and mean free paths of phonons. Since both intercalation and strain can be applied reversibly, their stark effect on thermal conductivity can be exploited to design novel phononic devices, as well as for thermal management in MoS2-based electronic and optoelectronic systems.