LiZn(OH)CO3: A Deep-Ultraviolet Nonlinear Optical Hydroxycarbonate Designed from Diamond-like Structure.

The deep-ultraviolet (DUV) nonlinear optical (NLO) crystals are vital to the development of science and state-of-the-art technologies, but the exploration of these important optoelectronic materials is hindered by the contradiction between NLO effect and energy band gap as well as the sensitivity of DUV phase-matching to optical birefringence. Here, in order to achieve the well balanced DUV NLO performance, we chose the diamond-like structure as the prototype template for the material design and synthesize the first DUV NLO hydroxycarbonate crystal LiZn(OH)CO3. This compound simultaneously has wide band gap (> 6.53 eV), strong second harmonic generation response (~3.2 × KDP), and large birefringence (0.147@1064 nm) with the shortest DUV phase-matching capability (λPM < 190 nm) among all reported NLO carbonates. Moreover, the structure-property relationships in LiZn(OH)CO3 are analyzed by first-principles calculations. This work presents an effective design strategy to push the NLO performance of hydroxycarbonates into the DUV region.