講演情報
[23a-A202-8]Curvature-induced polarization in TMDC
〇高 燕林1、岡田 晋1 (1.筑波大学)
キーワード：
Janus TMDC,Density functional theory,Electrostatic potential difference
Transition metal dichalcogenides (TMDCs) are representative atomic layer materials which possess tunable electronic structure in terms of their constituent elements and morphologies. Most TMDC, MX2 where M and X are a transition metal and chalcogen atoms, respectively, have semiconducting electronic structure whose band gap is sensitive to the constituent elements. In addition, the TMDC can form Janus structures MXX’ where metal atomic layer is sandwiched by different chalcogen layers leading to the polarization across the layers. Introduced wrinkles or corrugations make TMDCs unique in-plane heterostructures which are semiconductors with type-II band edge alignment between curved and flat regions owing to the polarization by curvature [1]. The fact implied that the TMDCs with structural corrugation or wrinkles can be regarded as Janus TMDCs in terms of their electrostatic properties. However, systematic analysis of polarization of TMDCs with curvature is absent to date. Thus, in this work, we aim to investigate the electrostatic properties of TMDC with respect to their curvature using the density functional theory with effective screening medium method. The curvature of TMDCs is modeled by TMDC nanotube (NT) with the diameter ranging from 1.5 to 4.0 nm. We found that the finite electrostatic potential difference between inside and outside NTs, indicating that the curvature causes the polarization across the layers. The potential difference between outside and inside the NTs monotonically decreases with increasing diameter (Fig.1). The largest polarization is 0.094 V at the WS2-NT with a diameter of 1.4 nm, which is smaller than that of Janus TMDCs.