Temperature and Thickness Dependence of the Thermal Conductivity in 2D Ferromagnet FeGeTe.

The emergence of symmetry-breaking orders such as ferromagnetism and the weak interlayer bonding in van der Waals materials offers a unique platform to engineer novel heterostructures and tune transport properties like thermal conductivity. Here, we report the experimental and theoretical study of the cross-plane thermal conductivity, κ, of the van der Waals two-dimensional (2D) ferromagnet FeGeTe. We observe an increase in κ with thickness, indicating a diffusive transport regime with ballistic contributions.

Anharmonicity Reveals the Tunability of the Charge Density Wave Orders in Monolayer VSe.

VSe is a layered compound that has attracted great attention due to its proximity to a ferromagnetic state that is quenched by its charge density wave (CDW) phase. In the monolayer limit, unrelated experiments have reported different CDW orders with different transition temperatures, making this monolayer very controversial. Here we perform first-principles nonperturbative anharmonic phonon calculations in monolayer VSe in order to estimate the CDW order and the corresponding transition temperature.