새소식

Department of Physics & Astronomy

[손병민/김정래 박사, 노태원/김창영 교수] 단원자층 산화물의 금속성 관측 (Nature Communications 논문 게재)

2021-10-28l 조회수 416

“Observation of metallic electronic structure in a single-atomic-layer oxide”

단원자층의 산화물 박막이 도체로 남아 있을 수 있는가는 중요한 의문으로 남아 있었는데, 이는 단원자층의 전기 전도도를 측정할 수 있는 적절한 방법이 없었기 때문이다. 본 연구에서는 각도분해 광전자분광법의 표면민감성 및 특이 이종접합 구조를 이용하여 단원자층의 SrRuO3가 금속성을 가지고 있다는 것을 실험적으로 규명하였다. 또한 이러한 금속 상태가 특이한 correlated metallic 상태로 존재하는 것을 발견하였다. 이러한 발견 및 방법론 개발은 향 후 단원자층 박막에 대한 많은 연구를 촉발 할 수 있을 것으로 기대된다.   

Correlated electrons in transition metal oxides exhibit a variety of emergent phases. When transition metal oxides are confined to a single-atomic-layer thickness, experiments so far have shown that they usually lose diverse properties and become insulators. In an attempt to extend the range of electronic phases of the single-atomic-layer oxide, we search for a metallic phase in a monolayer-thick epitaxial SrRuO3 film. Combining atomic-scale epitaxy and angle-resolved photoemission measurements, we show that the monolayer SrRuO3 is a strongly correlated metal. Systematic investigation reveals that the interplay between dimensionality and electronic correlation makes the monolayer SrRuO3 an incoherent metal with orbital-selective correlation. Furthermore, the unique electronic phase of the monolayer SrRuO3 is found to be highly tunable, as charge modulation demonstrates an incoherent-to-coherent crossover of the two-dimensional metal. Our work emphasizes the potentially rich phases of single-atomic-layer oxides and provides a guide to the manipulation of their two-dimensional correlated electron systems.

Authors: Byungmin Sohn# (서울대, IBS CCES), Jeong Rae Kim# (서울대, IBS CCES), Choong H. Kim, Sangmin Lee, Sungsoo Hahn, Younsik Kim, Soonsang Huh, Donghan Kim, Youngdo Kim, Wonshik Kyung, Minsoo Kim, Miyoung Kim, Tae Won Noh* (서울대, IBS CCES), and Changyoung Kim* (서울대, IBS CCES)

Publication date: 26 October 2021 

Link: https://doi.org/10.1038/s41467-021-26444-z