Spectral weight reduction of two-dimensional electron gases at oxide surfaces across the ferroelectric transition

• Published in: Scientific reports Vol. 10; no. 1; p. 16834
• Main Authors: Jaiban, P, Lu, M-H, Eknapakul, T, Chaiyachad, S, Yao, S H, Pisitpipathsin, N, Unruan, M, Siriroj, S, He, R-H, Mo, S-K, Watcharapasorn, A, Yimnirun, R, Tokura, Y, Shen, Z-X, Hwang, H Y, Maensiri, S, Meevasana, W
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 08.10.2020; Nature Publishing Group UK
• Subjects: electronic properties and materials; ferroelectrics and multiferroics; MATERIALS SCIENCE; phase transitions and critical phenomena
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-73657-1

The discovery of a two-dimensional electron gas (2DEG) at the [Formula: see text] interface has set a new platform for all-oxide electronics which could potentially exhibit the interplay among charge, spin, orbital, superconductivity, ferromagnetism and ferroelectricity. In this work, by using angle-resolved photoemission spectroscopy and conductivity measurement, we found the reduction of 2DEGs and the changes of the conductivity nature of some ferroelectric oxides including insulating Nb-lightly-substituted [Formula: see text], [Formula: see text] (BTO) and (Ca,Zr)-doped BTO across paraelectric-ferroelectric transition. We propose that these behaviours could be due to the increase of space-charge screening potential at the 2DEG/ferroelectric regions which is a result of the realignment of ferroelectric polarisation upon light irradiation. This finding suggests an opportunity for controlling the 2DEG at a bare oxide surface (instead of interfacial system) by using both light and ferroelectricity.