Zhang Jian-Bo, Struzhkin Viktor V, Yang Wenge, Mao Ho-Kwang, Lin Hai-Qing, Ma Yong-Chang, Wang Nan-Lin, Chen Xiao-Jia
Department of Physics, South China University of Technology, Guangzhou 510640, People's Republic of China. Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, People's Republic of China. Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, USA.
J Phys Condens Matter. 2015 Nov 11;27(44):445701. doi: 10.1088/0953-8984/27/44/445701. Epub 2015 Oct 13.
The systematic evolution of the structural, vibrational, and superconducting properties of nearly optimally doped Tl2Ba2CaCu2O(8+δ) with pressure up to 30 GPa is studied by x-ray diffraction, Raman scattering, and magnetic susceptibility measurements. No phase transformation is observed in the studied pressure regime. The obtained lattice parameters and unit-cell volume continuously decrease with pressure by following the expected equation of state. The axial ratio of c/a exhibits an anomaly starting from 9 GPa. At such a pressure level, the deviation from the nonlinear variation of the phonon frequencies is detected. Both the above observations indicate the enhancement of the distortion upon compression. The superconducting transition temperature is found to exhibit a parabolic behavior with a maximum of 114 K around 7 GPa. We demonstrate that the interplay between the intrinsic pressure variables and distortion controls the superconductivity.
通过X射线衍射、拉曼散射和磁化率测量，研究了近最佳掺杂的Tl2Ba2CaCu2O(8+δ)在高达30 GPa压力下结构、振动和超导性质的系统演化。在所研究的压力范围内未观察到相变。获得的晶格参数和单胞体积随压力按照预期的状态方程持续减小。c/a轴比从9 GPa开始出现异常。在这样的压力水平下，检测到声子频率非线性变化的偏差。上述两个观察结果均表明压缩时畸变增强。发现超导转变温度呈现抛物线行为，在7 GPa左右达到最大值114 K。我们证明了内在压力变量和畸变之间的相互作用控制着超导性。
