Band-gap of bulk solids and two-dimensional bent nanoribbons from first-principles*

Two dimensional materials (2D) are of interest due to their remarkable physical and chemical properties. Bending is the computationally efficient route to tune fundamental/optical gaps for device functionality [1]. Accurately predicting band-gaps is one of the critical challenges in density functional theory (DFT). In this work, we test the band-gap of bulk solids and 2D materials from semi-local functionals and the hybrid HSE06 functional. In addition, we use the GW approach. GW provides the most physically grounded way to accurately predict the band-gaps on the basis of quasiparticle energies with a high computational cost. We are particularly focusing on non-empirical meta-GGA functionals developed for band-gap prediction [2], as computationally cheaper alternatives to hybrid functionals and GW approximations. We are investigating how the accuracy of such meta-GGAs can be improved for the band-gap of low-dimensional materials.

[1] L. Yu, A. Ruzsinszky, J.P. Perdew, Nano Lett. 16, 2444 (2016)
[2] T. Aschebrock and S. Kümmel, Phys. Rev. Research, 1, 033082 (2019)