A unified model for the uniaxial and hydrostatic pressure dependence of T-c in YBa2Cu3Ox (x approximate to 6.95-7.0)
A unified model for the uniaxial and hydrostatic pressure dependence of T-c in YBa2Cu3Ox (x approximate to 6.95-7.0)
复制标题
YBa2Cu3Ox 中 T-c 的单轴和静水压力依赖性的统一模型（x 近似于 6.95-7.0）
DOI：
10.1016/j.commatsci.2018.07.004
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发表时间：
2018
影响因子：
3.3
通讯作者：
Jiang Zhao Fei
中科院分区：
文献类型：
--
作者：
Cao Jin Jin;Gou Xiao Fan;Wang Tian Ge;Jiang Zhao Fei
虽然Tcyield的单轴和流体静压的依赖性是对YBa_2Cu_3 Ox（x = 6.95-7.0）超导性的重要认识，但对该系统的压力效应的起源仍缺乏统一的定量模型解释。为了建立一个统一的模型，我们对YBa_2Cu_3O_7在压力下进行了第一性原理计算，以区分空穴浓度和四方性等核心因素，并进一步将这两个因素与电荷转移模型相结合来确定Tc。四方性在单轴压力效应中起重要作用，但在产生YBa_2Cu_3 Ox（x = 6.95-7.0）的超导电性中，四方性的作用不如空穴浓度那么显著。基于新定义的四方性和空穴浓度的统一模型在压力作用下的计算结果与实验结果吻合较好。在此统一模型下，我们预言YBa_2Cu_3 Ox（x = 6.95-7.0）在沿轴压缩0.025或沿轴拉伸0.025时，可能出现较好的超导电性。
Though the uniaxial and hydrostatic pressure dependence ofTcyield important insight into the superconductivity of YBa2Cu3Ox(x≈ 6.95–7.0), the understanding of the origin of the pressure effect on this system remains lack of a unified model explanation in a quantitative manner. In order to develop a unified model, we performed first-principles calculations for YBa2Cu3O7under pressure to distinguish the core factors including holes concentration and tetragonality and further combined the two factors with the charge-transfer model to determine theTc. The role of tetragonality was identified in determining the uniaxial pressure effect significantly but not as prominent as holes concentration in producing the superconductivity of YBa2Cu3Ox(x≈ 6.95–7.0). The results under pressure from the unified model based on the newly defined tetragonality and holes concentration are in good accordance with that from experiments. With this unified model, we predicted that the better superconductivity in YBa2Cu3Ox(x≈ 6.95–7.0) may appear through 0.025 compression alongbaxis or 0.025 stretching alongaaxis.