The temperature dependence of the band structures in mono-layer, few-layer and bulk black phosphorus

Black phosphorus (BP), an emerging two-dimensional material, has attracted abundant research interests. However, the study of temperature dependence of the bandgap in few-layer BP is still lacking. Here we systematically investigated the temperature dependence of the electronic structures in mono-layer, few-layer and bulk BP. We found that the temperature dependence of the electronic structure has strong layer and transition-index dependence, which is closely related to the temperature dependent interlayer interaction. Surprisingly, the band gaps of monolayer and bulk BP showed opposite temperature effect. Such diverse behavior sheds light on the importance of van der Waals coupling in defining the electronic structures of 2D materials.