De Renzi R, Coneri F, Mezzadri F, Allodi G, Calestani G, Righi L, Lopez G M, Fiorentini V, Filippetti A, Sanna S
Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco delle Scienze 7/a, 43124 Parma, Italy.
J Phys Condens Matter. 2019 May 8;31(18):184002. doi: 10.1088/1361-648X/ab053c. Epub 2019 Feb 7.
We investigate the specific influence of structural disorder on the suppression of antiferromagnetic order and on the emergence of cuprate superconductivity. We single out pure disorder, by focusing on a series of [Formula: see text] samples at fixed oxygen content y = 0.35, in the range [Formula: see text]. The gradual Y/Eu isovalent substitution smoothly drives the system through the Mott-insulator to superconductor transition from a full antiferromagnet with Néel transition [Formula: see text] K at z = 0 to a bulk superconductor with superconducting critical temperature [Formula: see text] K at z = 1, [Formula: see text]. The electronic properties are finely tuned by gradual lattice deformations induced by the different cationic radii of the two lanthanides, inducing a continuous change of the basal Cu(1)-O chain length, as well as a controlled amount of disorder in the active Cu(2)O bilayers. We check that internal charge transfer from the basal to the active plane is entirely responsible for the doping of the latter and we show that superconductivity emerges with orthorhombicity. By comparing transition temperatures with those of the isoelectronic clean system we determine the influence of pure structural disorder connected with the Y/Eu alloy.
我们研究了结构无序对反铁磁序抑制以及铜酸盐超导性出现的具体影响。通过聚焦于一系列固定氧含量(y = 0.35)、在([公式：见正文])范围内的([公式：见正文])样品，我们分离出了纯无序。逐渐进行的钇/铕等价取代使系统平稳地从具有奈尔转变温度([公式：见正文]) (K)（(z = 0)时）的完全反铁磁体经过莫特绝缘体到超导体的转变，变为在(z = 1)时具有超导临界温度([公式：见正文]) (K)的体超导体([公式：见正文])。电子性质通过由两种镧系元素不同阳离子半径引起的逐渐晶格变形进行精细调节，这导致了基底Cu(1)-O链长度的连续变化，以及活性Cu(2)O双层中可控量的无序。我们验证了从基底平面到活性平面的内部电荷转移完全是后者掺杂的原因，并且我们表明超导性伴随着正交性出现。通过将转变温度与等电子清洁系统的转变温度进行比较，我们确定了与钇/铕合金相关的纯结构无序的影响。
