| AVS 66th International Symposium & Exhibition | |
| 2D Materials | Wednesday Sessions |
| Session 2D+EM+MI+MN+NS+QS-WeM |
| Session: | Novel 2D Materials |
| Presenter: | Yaxian Wang, The Ohio State University |
| Authors: | Y. Wang, The Ohio State University B. He, The Ohio State University M.Q. Arguilla, The Ohio State University N.D. Cultrara, The Ohio State University M.R. Scudder, The Ohio State University J.E. Goldberger, The Ohio State University J.P. Heremans, The Ohio State University W. Windl, The Ohio State University |
| Correspondent: | Click to Email |
NaSn2As2 has recently been synthesized and was found to be an exfoliatable van der Waals Zintl phase, opening new opportunities for electronic design on the few-atom-thick scale. Although the band structure may suggest a range of metal to semi-metal, it shows strong anisotropy especially in its “polarity”, characterized by its dominant carrier type, which strongly affects its electronic and thermal properties. We used DFT calculations to investigate bandstructure and Fermi surface. In addition, we employed BoltzTraP code to calculate the transport behavior in in/cross-plane directions, predicting strongly anisotropic carrier transport and directionally dependent polarity –“goniopolarity” – in this layered material. It is confirmed by experimental thermopower measurements. We show from simulations on a model band structure the Fermi surface geometry origin in a single-band toy model, and we utilize the bandwidth concept from a tight-binding model to give an insight of real space orbital contributions and nature of the bonding states in this layered crystal. Based on that, additional candidate materials for goniopolarity can be proposed, and the design space for goniopolar materials in general will be defined.