First Principle Study of Nonlinear Optical Effects on 2D Ferromagnetic VSe2
Li Wei Chang1*, Guang Yu Guo1,2
1Physics, National Taiwan University, Taipei, Taiwan
2Physics, National Center for Theoretical Sciences, Taipei, Taiwan
* Presenter:Li Wei Chang,
2D Transition-metal dichalcogenides (TMDs) exhibit properties that are different from their bulk crystals. Recently, some experimental groups successfully synthesized a 2D type of TMDs, vanadium diselenide (VSe2). VSe2 is a ferromagnetic semiconductor in 2D 2H-phase, while it is a paramagnetic metal in bulk 1T-phase. Moreover, because of the inversion symmetry breaking, 2D VSe2 with an odd layer number shows the nonlinear optical properties. In this work, we use first principle method to study the H-phase monolayer and trilayer VSe2. We find large shift current and injection current in these 2D structures compared to other nonlinear optical materials. Also, we calculate the second harmonic generation and dielectric function. Our calculated nonlinear optical effects are in agreement with the available experimental results.

Keywords: 2D Transition-metal Dichalcogenides, VSe2, Nonlinear Optical Effects, First Principle Calculation