Uniaxial strain effects on the superconducting transition in Re-doped Hg-1223 cuprate superconductors
Uniaxial strain effects on the superconducting transition in Re-doped Hg-1223 cuprate superconductors
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DOI：
10.1103/physrevb.95.064503
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发表时间：
2017-02
影响因子：
3.7
通讯作者：
Mito Masaki;Ogata Kazuma;Goto Hiroki;Tsuruta Kazuki;Nakamura Kazuma;Deguchi Hiroyuki;H. Tomoya;Matsumoto Kaname;Tajiri Takayuki;Hara Hiroshi;Ozaki Toshinori;Takeya Hiroyuki;Takano Yoshihiko
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文献类型：
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作者：
Mito Masaki;Ogata Kazuma;Goto Hiroki;Tsuruta Kazuki;Nakamura Kazuma;Deguchi Hiroyuki;H. Tomoya;Matsumoto Kaname;Tajiri Takayuki;Hara Hiroshi;Ozaki Toshinori;Takeya Hiroyuki;Takano Yoshihiko
通过交流磁测量研究了单轴应变和静水压力对HgRe[Hg₀.₈₃(Re₀.₁₈)-1223]的影响，应力最大对应20 GPa的压力。根据先前基于埃伦费斯特关系的热学研究，面内收缩应提高超导转变温度（Tc），而面外收缩应降低Tc。这表明在静水压力收缩下Tc的升高必须小于面内收缩下的升高。然而，目前的单轴应变实验显示，面内和面外收缩下Tc均提高，且在静水压力收缩下观察到最大的提高。根据能带计算，所有收缩方式都会诱导从HgO层到CuO₂层的空穴掺杂，并且静水压力收缩在三种收缩中产生最大的空穴掺杂。这种行为很好地解释了在8 GPa以下应力区域中Tc的一系列变化。更具体地说，在静水压力收缩下，随着压力增加，Tc呈现出升高、降低和再次升高的变化，这种多步变化与在Bi - 2223型铜酸盐超导体中观察到的相似，这表明有必要区分应变对三CuO₂层结构中中间CuO₂层的影响与对外层的影响。
The effects of uniaxial strain and hydrostatic pressure on Hg Re [Hg 0 . 83 (Re 0 . 18 )-1223] were investigated by AC magnetic measurements under stress corresponding to a pressure of 20 GPa at maximum. According to a previous thermal study based on the Ehrenfest relation, in-plane contraction should increase the superconducting transition temperature ( T c ), whereas out-of-plane contraction should decrease T c . This suggests that the increase in T c under hydrostatic-pressure contraction must be smaller than that under in-plane contraction. However, the present uniaxial-strain experiments revealed enhancement of T c under both in-plane and out-of-plane contraction, and the largest enhancement was observed under hydrostatic-pressure contraction. According to a band calculation, all contraction styles induce hole doping from the HgO blocks to the CuO 2 blocks, and hydrostatic-pressure contraction yields the largest hole doping among three contractions. This behavior explains well a series of changes in T c in the stress region of below 8 GPa. More specifically, under hydrostatic-pressure contraction, T c exhibited an increase, a decrease, and another increase with increasing pressure, and this multistep change is similar to that observed in Bi-2223-type cuprate superconductors, suggesting that it is necessary to distinguish the effect of strain on the middle CuO 2 plane in the three-CuO 2 -plane package from that on the outer planes.