Electronic Structure and High Temperature Superconductivity of the FeSe /SrTiO3 Films

High resolution angle-resolved photoemission measurements have been carried out to study the electronic structure and high temperature superconductivity of the single-layer FeSe films grown on SrTiO3 substrate [1]. Distinct Fermi surface topology and nearly isotropic superconducting gap without nodes are observed in the system [2]. Phase diagram is established and electronic indication of high temperature superconductivity at $\sim$65K is observed in tuning the carrier concentration of the single-layer FeSe film [3]. With a variation of the charge carriers, an insulator-superconductor transition in the single-layer FeSe/SrTiO3 is observed. A dichotomy of electronic structure and superconductivity is revealed between the single-layer and double-layer FeSe/SrTiO3 films. Implications of these results on the superconductivity mechanism of the iron-based superconductors will be discussed. \\[4pt] References:\\[0pt] [1]. Qing-Yan WANG, Zhi LI, Wen-Hao ZHANG, Zuo-Cheng ZHANG, Jin-Song ZHANG, Wei LI, Hao DING, Yun-Bo OU, Peng DENG, Kai CHANG, Jing WEN, CanLi SONG, Ke HE, Jin-Feng JIA, Shuai-Hua JI, Ya-Yu WANG, Li-L WANG i, Xi CHEN, Xu-Cun MA, Qi-Kun XUE, Chinese Physics Letters 29 (2012) 037402.\\[0pt] [2]. Defa Liu*, Wenhao Zhang*, Daixiang Mou*, Junfeng He*, Yun-Bo Ou, Qing-Yan Wang, Zhi Li, Lili Wang, Lin Zhao, Shaolong He, Yingying Peng, Xu Liu, Chaoyu Chen, Li Yu, Guodong Liu, Xiaoli Dong, Jun Zhang, Chuangtian Chen, Zuyan Xu, Jiangping Hu, Xi Chen, Xucun Ma, Qikun Xue, and X. J. Zhou, Nature Communications 3 (2012) 931.\\[0pt] [3]. Shaolong He*, Junfeng He*, Wenhao Zhang*, Lin Zhao*, Defa Liu, Xu Liu, Daixiang Mou, Yun-Bo Ou, Qing-Yan Wang, Zhi Li, Lili Wang, Yingying Peng, Yan Liu, Chaoyu Chen, Li Yu, Guodong Liu, Xiaoli Dong, Jun Zhang, Chuangtian Chen, Zuyan Xu, Xi Chen, Xucun Ma, Qikun Xue, and X. J. Zhou, Nature Materials 12 (2013) 605.