Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, USA.
Science. 2014 Jul 11;345(6193):187-90. doi: 10.1126/science.1251151. Epub 2014 Jun 12.
High-temperature superconductivity in cuprates arises from an electronic state that remains poorly understood. We report the observation of a related electronic state in a noncuprate material, strontium iridate (Sr2IrO4), in which the distinct cuprate fermiology is largely reproduced. Upon surface electron doping through in situ deposition of alkali-metal atoms, angle-resolved photoemission spectra of Sr2IrO4 display disconnected segments of zero-energy states, known as Fermi arcs, and a gap as large as 80 millielectron volts. Its evolution toward a normal metal phase with a closed Fermi surface as a function of doping and temperature parallels that in the cuprates. Our result suggests that Sr2IrO4 is a useful model system for comparison to the cuprates.
高温超导电性在铜酸盐中产生，但其电子态仍未得到很好的理解。我们报告了在一种非铜酸盐材料锶铱氧化物（Sr2IrO4）中观察到的相关电子态，其中明显的铜酸盐费米子学得到了很大程度的再现。通过原位沉积碱金属原子对表面电子进行掺杂，Sr2IrO4 的角分辨光电子能谱显示出零能态的不连续片段，即费米弧，以及高达 80 毫电子伏特的能隙。随着掺杂和温度的变化，它向具有封闭费米面的正常金属相的演化与铜酸盐的演化相似。我们的结果表明，Sr2IrO4 是一个有用的模型系统，可与铜酸盐进行比较。
