Atomic‐scale metal–insulator transition in SrRuO3 ultrathin films triggered by surface termination conversion

DOI: 10.1002/adma.201905815

Authors: Han Gyeol Lee (Institute for Basic Science (IBS), Seoul; Seoul National University) , Lingfei Wang (Institute for Basic Science (IBS), Seoul; Seoul National University) , Liang Si (Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences; Institut für Festkörperphysik) , Xiaoyue He (National University of Singapore; Songshan Lake Materials Laboratory) , Daniel G. Porter (Diamond Light Source) , Jeong Rae Kim (Institute for Basic Science (IBS), Seoul; Seoul National University) , Eun Kyo Ko (Institute for Basic Science (IBS), Seoul; Seoul National University) , Jinkwon Kim (Institute for Basic Science (IBS), Seoul; Seoul National University) , Sung Min Park (Institute for Basic Science (IBS), Seoul; Seoul National University) , Bongju Kim (Institute for Basic Science (IBS), Seoul; Seoul National University) , Andrew Thye Shen Wee (National University of Singapore) , Alessandro Bombardi (Diamond Light Source) , Zhicheng Zhong (Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences; University of Chinese Academy of Sciences) , Tae Won Noh (Institute for Basic Science (IBS), Seoul; eoul National University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Advanced Materials , VOL 9

State: Published (Approved)
Published: December 2019
Diamond Proposal Number(s): 22181

Abstract: The metal–insulator transition (MIT) in transition‐metal‐oxide is fertile ground for exploring intriguing physics and potential device applications. Here, an atomic‐scale MIT triggered by surface termination conversion in SrRuO3 ultrathin films is reported. Uniform and effective termination engineering at the SrRuO3(001) surface can be realized via a self‐limiting water‐leaching process. As the surface termination converts from SrO to RuO2, a highly insulating and nonferromagnetic phase emerges within the topmost SrRuO3 monolayer. Such a spatially confined MIT is corroborated by systematic characterizations on electrical transport, magnetism, and scanning tunneling spectroscopy. Density functional theory calculations and X‐ray linear dichroism further suggest that the surface termination conversion breaks the local octahedral symmetry of the crystal field. The resultant modulation in 4d orbital occupancy stabilizes a nonferromagnetic insulating surface state. This work introduces a new paradigm to stimulate and tune exotic functionalities of oxide heterostructures with atomic precision.

Journal Keywords: epitaxial ultrathin films; ferromagnetism; metal–insulator transition; SrRuO3; surface termination engineering

Diamond Keywords: Ferromagnetism

Subject Areas: Materials, Physics


Instruments: I16-Materials and Magnetism

Added On: 16/12/2019 14:33

Discipline Tags:

Surfaces Quantum Materials Hard condensed matter - electronic properties Physics Magnetism Materials Science interfaces and thin films

Technical Tags:

Spectroscopy Linear Dichroism (LD)