[14a-2H-1~11] 6.3 Oxide electronics

[14a-2H-9] Interface induced spontaneous polarization in an oxide heterojunction

〇Masao Nakamura¹, Fumitaka Kagawa¹, Toshiaki Tanigaki¹, Hyun Soon Park¹, Tsuyoshi Matsuda², Daisuke Shindo^1,3, Yoshinori Tokura^1,4, Masashi Kawasaki^1,4 (1.RIKEN-CEMS, 2.JST, 3.Tohoku Univ., 4.Univ. of Tokyo)

Keywords:Oxide heterojunction,Spontaneous polarization,Photovoltaics

We have investigated in detail the electronic structure of LaFeO₃/SrTiO₃ heterojunctions with the interfacial polar discontinuity. Photovoltaic measurements, electron holography, and piezoresponse force microscopy on the heterojunction indicate that a spontaneous polarization is induced in the originally non-polar LaFeO₃. We conclude that the spontaneous polarization is triggered by the electronic reconstruction or so-called polar catastrophe which necessarily occurs to screen the bound charges originated from the polar discontinuity.