Electronic structure and nematic phase transition in superconducting multiple-layer FeSe films grown by pulsed laser deposition method

Shen Bing^{1, 2}, Feng Zhong-Pei^{1, 2}, Huang Jian-Wei^{1, 2}, Hu Yong^{1, 2}, Gao Qiang^{1, 2}, Li Cong^{1, 2}, Xu Yu^{1, 2}, Liu Guo-Dong¹, Yu Li¹, Zhao Lin^{1, †}, Jin Kui^{1, ‡}, Zhou X J^{1, 2, 3, §}

Fermi surface and band structure of the S4K sample measured at 30 K before and after potassium deposition. (a1) and (a2) are Fermi surface mapping of the S4K sample measured before and after potassium deposition, respectively. They are obtained by integrating the spectral weight with [−20 meV, 10 meV] energy window with respect to the Fermi level. (b1)–(b3) show the original data measured on the S4K sample before potassium deposition along three momentum cuts crossing , M2, and M3, respectively. The locations of the three momentum cuts are marked in (a1) by red lines. (b4)–(b6) are second derivative images with respect to energy corresponding to their original data (b1)–(b3). (c1)–(c3) and (c4)–(c6) show original data along three momentum cuts after potassium deposition, and their corresponding second derivative images, respectively.