Beijing National Laboratory for Condensed Matter Physics, Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China.
School of Physics , University of Chinese Academy of Sciences , Beijing 100190 , China.
Inorg Chem. 2018 May 7;57(9):5108-5113. doi: 10.1021/acs.inorgchem.8b00171. Epub 2018 Apr 9.
A new layered oxyselenide, BaCuOCuSe, was synthesized under high-pressure and high-temperature conditions and was characterized via structural, magnetic, and transport measurements. It crystallizes into space group I4/ mmm and consists of a square lattice of [CuO] planes and antifluorite-type [CuSe] layers, which are alternately stacked along the c axis. The lattice parameters are obtained as a = b = 4.0885 Å and c = 19.6887 Å. The Cu-O bond length is given by half of the lattice constant a, i.e., 2.0443 Å. BaCuOCuSe is a semiconductor with a resistivity of ∼18 mΩ·cm at room temperature. No magnetic transition was found in the measured temperature range, and the Curie-Weiss temperature was obtained as -0.2 K, suggesting a very weak exchange interaction. The DFT+ U calculation demonstrates that the band gap is about 0.2 eV for the supposed antiferromagnetic order, and the density of state near the top of the valence band is mainly contributed from the Se 4p electrons.
一种新型的层状氧硒化物 BaCuOCuSe 在高温高压条件下合成，并通过结构、磁性和输运测量进行了表征。它结晶为 I4/mmm 空间群，由[CuO]平面的正方形晶格和反萤石型[CuSe]层组成，这些层沿 c 轴交替堆叠。晶格参数为 a = b = 4.0885 Å 和 c = 19.6887 Å。Cu-O 键长由晶格常数 a 的一半给出，即 2.0443 Å。BaCuOCuSe 是一种半导体，室温下的电阻率约为 18 mΩ·cm。在所测量的温度范围内未发现磁转变，居里-外斯温度为-0.2 K，表明交换相互作用非常弱。DFT+U 计算表明，对于假设的反铁磁有序，带隙约为 0.2 eV，价带顶部的态密度主要由 Se 4p 电子贡献。
