Orientation-dependent crack patterns at the surface of SrTiO₃ crystals induced by laser irradiation

Laser irradiation offers a unique ability to bring about desired material modification. Here, orientation-dependent crack patterns appear on the surface of SrTiO₃ (STO) crystals after laser irradiation. Atomic force microscopy and scanning electron microscopy characterizations reveal rectangular crack patterns on (110) STO surface and polygonal patterns on (111) STO surface. The microcrack patterns are expected to result from the release of residual stresses after local heating. At the same time, an insulator-metal transition has been observed after laser irradiation, which is attributed to laser-induced oxygen vacancies. Our findings are helpful for a deeper understanding of light-matter interaction and the development of relevant applications.