非线性光学数据库:理论预测助力材料的快速发现

A prediction-driven database to enable rapid discovery of nonlinear optical materials

现代激光技术迫切需要能够通过二次谐波产生相干光的非线性光学材料.然而,只有很少一部分非中心对称晶体材料的非线性光学性质被实验或者理论研究,针对高性能非线性光学晶体材料的探索仍非常有限.本工作建立了迄今为止最大的计算非线性光学晶体材料数据库,其中包含2354个非中心对称晶体结构,以及它们的倍频系数和带隙.本文提供了理论数据的计算细节和其与实验数据的对比验证,以及数据库的详细描述.该数据库的重要特点之一是它包含大量通过进化算法搜索发现的新的热力学稳定和亚稳定结构,这为寻找具有更好性能的新型非线性光学材料提供了可能性.

Nonlinear optical(NLO)materials capable of generating coherent light by second harmonic generation(SHG)are urgently needed in modern laser technology.De-spite the importance of this class of materials,only a small fraction of non-centrosymmetric(NCS)crystalline com-pounds with finite electronic band gaps which exhibit SHG response have been studied experimentally or theoretically,and thus an efficient exploration of NLO materials with high performance is greatly limited.In this work,we introduce to date the largest computational NLO materials database which contains calculated SHG coefficients for 2354 NCS crystal structures as well as their electronic band gaps.The compu-tational details and validation of data are presented,along with a detailed description of the database helpful for the usage of these computational results.One of the main features of the present database is that it contains a large number of new thermodynamically stable and metastable structures dis-covered through evolutionary algorithm searches,providing possibilities for finding novel NLO materials with good properties.