Photonic control of electronic properties has been of current interest in condensed matter physics. One of the important candidate materials is spin crossover (SC) complexes, which are known to show so called photoinduced phase transition (PIPT). This is a photonic change/control of the spin state of d electrons in the transition metal element between the low spin (LS) state (t2g6) and the high spin (HS, eg2 t2g4) state. In addition to those organic complexes, a perovskite-type cobalt oxide is also an interesting example showing such a spin state transition with an insulator-metal transition, and we have revealed that some SC cobalt oxides showed unique ultarafast PIPT[1-5]. In this presentation, we show a PIPT phenomenon in a perovskite-type cobalt oxide, Pr0.5Ca0.5CoO3 undergoing the SC between the LS and the intermediate spin (IS, eg1 t2g5) state, and discuss the real space dynamics of the photoinduced metallic area after the photoirradiation in terms of the electromagnetic analysis.

References
[1]Y. Okimoto et al., Phys, Rev. Lett. 103, 027402 (2009).
[2]Y. Okimoto et al., Phys, Rev. B 83, 161101(R) (2011).
[3]Y. Okimoto et al., Phys. Rev. B, 84, 121102(R) (2011).
[4]K. Seko, Y. Okimoto et al., Act. Phys. Pol. A, 121, 369 (2012).
[5]Y. Okimoto et al., J. Phys. Soc. Jpn., 82, 187401 (2013).