Electronic structure studies on exotic insulating state in La_xSr_2-xRhO₄

So far, there have been a lot of researches on Sr₂IrO₄ due to its exotic insulating behavior. With the help of experiemental and theoretical studies, it is well known that J_eff, caused by strong spin-orbit coupling, make it Mott insulator. On the other hand, although Rh is isovalent of Ir, Sr₂RhO₄ is a metal because of the smaller SOC effect comparing to Sr₂IrO₄. Interestingly, however, we has been confirmed that it has an insulating state above specific electron doping number which was achieved through La substitution. We conducted electronic structure measurement studies to reveal the mechanism.