Isaenko Lyudmila, Dong Linfeng, Melnikova Svetlana V, Molokeev Maxim S, Korzhneva Ksenia E, Krinitsin Pavel G, Kurus Alexey F, Samoshkin Dmitry A, Belousov Roman A, Lin Zheshuai
Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk State University, Novosibirsk 630090, Russia.
Functional Crystals Lab, Technical Institute of Physics and Chemistry, CAS, University of Chinese Academy of Sciences, Beijing 100190, China.
Inorg Chem. 2024 May 27;63(21):10042-10049. doi: 10.1021/acs.inorgchem.4c01341. Epub 2024 May 15.
Phase transitions can change the crystal structure and modify the physical properties of crystals. In this work, we investigate the phase transition behavior in BaGaSe, an important middle infrared (mid-IR) nonlinear optical (NLO) crystal, in the temperature range from room temperature to 1173 K. Interestingly, the BaGaSe crystal undergoes a reversible ferroelastic phase transition at = 528 K, resulting in the presence of a newly discovered phase (γ-phase) at the higher temperature. The experimental temperature dependence of optical birefringence, as well as the first-principles birefringence and NLO coefficients, reveals that the γ-phase exhibits larger birefringence and better NLO properties compared with those of the low-temperature phase (α-phase). This work demonstrates that phase-transition-induced structural modification can improve the mid-IR NLO properties, which would provide an effective avenue to obtain materials with good optoelectronic performance.
