[Donghan Kim, Younsik Kim and Prof. Changyoung Kim] Electric control of Two-Dimensional Van Hove Singularity in Oxide Ultra-Thin Films (Advanced Materials)
Divergent density of states (DOS) can induce extraordinary phenomena such as significant enhancement of superconductivity and unexpected phase transitions. Moreover, van Hove singularities (VHSs) lead to divergent DOS in two-dimensional (2D) systems. Despite recent interest in VHSs, only a few controllable cases have been reported to date. In this work, by utilizing atomically thin SrRuO3 films, the electronic band structure of a 2D VHS is investigated with angle-resolved photoemission spectroscopy and transport properties are controlled. By applying electric fields with alkali metal deposition and ionic-liquid gating methods, we precisely control the 2D VHS, and the sign of the charge carrier. Use of a tunable 2D VHS in an atomically flat oxide film could serve as a new strategy to realize infinite DOS near the Fermi level, thereby allowing efficient tuning of electric properties.
Authors: Donghan Kim* (서울대, IBS-CCES), Younsik Kim* (서울대, IBS-CCES), Byungmin Sohn* (서울대, IBS-CCES), Minsoo Kim, Bongju Kim, Tae Won Noh, Changyoung Kim* (서울대, IBS-CCES)
Publication date: 10 February 2023
Link: https://doi.org/10.1002/adma.202207188