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BaAs2: an arsenide with giant second harmonic generation enabled by interesting As-As bonds
Qiang Liu1,2,3, Guili Wang1,2, Pifu Gong4
1Beijing Center for Crystal Research and Development, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China. jyao@mail.ipc.ac.cn.
Abstract:
The second harmonic generation (SHG) response of BaAs2, which features As-As bonds beneficial for the nonlinear optical (NLO) properties, was reported for the first time in this work. BaAs2 crystallizes in the monoclinic Pc space group with a non-centrosymmetric (NCS) structure, and it is a direct band gap semiconductor material with a band gap of 0.77 eV. The SHG measurements show that the SHG intensity of BaAs2 is 1.2 times that of CdGeAs2. Theoretical calculations indicate that the NLO effect of BaAs2 mainly originates from the [As-] chains, and its maximum second-order NLO coefficient is 146.02 pm V-1.
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