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arXiv · 1901.10058

Engineering Dirac states in graphene: Coexisting type-I and type-II Floquet-Dirac fermions

Hang Liu·Jia-Tao Sun·Sheng Meng
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Abstract

The coupling of monochromatic light fields and solids introduces nonequilibrium Floquet states, offering opportunities to create and explore new topological phenomena. Using combined first-principles and Floquet analysis we show that one can freely engineer Floquet-Dirac fermions (FDFs) in graphene by tuning the frequency and intensity of linearly polarized light. Not only type-II FDFs are created, but they also coexist with type-I FDFs near the Fermi level. Intriguingly, novel topologically nontrivial edge states connecting type-I and type-II Floquet-Dirac points emerge in photodriven graphene, providing an ideal channel to realize electron transport between the two types of Dirac states. Simulating time- and angle-resolved photoelectron spectroscopy suggests that the new coexisting state of type-I and type-II fermions is experimentally accessible. This work implies that a rich FDF phenomenon can be engineered in atomically thin graphene, hinting for developments of novel optoelectronic and quantum computing devices.

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Hang Liu, Jia-Tao Sun, Sheng Meng. 2019-01-29. Engineering Dirac states in graphene: Coexisting type-I and type-II Floquet-Dirac fermions. https://doi.org/10.1103/physrevb.99.075121

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