ワタナベ　ツトム   Tsutomu Watanabe   渡邉　努    所属   千葉工業大学  先進工学部 教育センター（先進工学部）    職種   教授
言語種別	英語
発行・発表の年月	2013/03
形態種別	学術雑誌
査読	査読あり
標題	Band and Mott Insulators and Superconductivity in Honeycomb-Lattice Ionic-Hubbard Model
執筆形態	共著
掲載誌名	Journal of the Physical Society of Japan
出版社・発行元	The Physical Society of Japan
巻・号・頁	82(3),pp.034704-1-034704-7
著者・共著者	Tsutomu Watanabe, Sumio Ishihara
概要	Motivated by superconductivity (SC) in layered nitrides, we study an ionic-Hubbard model of a honeycomb lattice, by an optimization variational Monte Carlo method. The origins of the band insulator and the SC state are investigated in the model. It is found that, in a weakly doped band insulator, spin fluctuation remains and the spin-singlet d-wave SC state is realized. Our results support an unconventional spin-singlet SC state suggested by the experimental observations in layered nitrides.