Inverse correlation between quasiparticle mass and T c in a cuprate high-T c superconductor.
Inverse correlation between quasiparticle mass and T c in a cuprate high-T c superconductor.
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DOI：
10.1126/sciadv.1501657
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发表时间：
2016-03
期刊：
影响因子：
13.6
通讯作者：
Carrington A
中科院分区：
文献类型：
--
作者：
Putzke C;Malone L;Badoux S;Vignolle B;Vignolles D;Tabis W;Walmsley P;Bird M;Hussey NE;Proust C;Carrington A
与量子临界点附近的预期相反，压力降低了高tc超导体的准粒子质量。在有序和无序电子相之间接近零温度的转变，量子涨落可以导致电子质量的强烈增强和竞争相的出现，如超导性。在一些重费米子和铁基超导体中，这种量子相变的存在与超导性之间的相关性已经很好地建立起来，并且有人认为氧化铜材料（铜酸盐）中的高温超导性也可能由相同的机制驱动。在铜酸盐中，接近最佳掺杂的超导转变温度Tc是最大的，已知有两种不同的相与超导性竞争：一个鲜为人知的假间隙相和一个电荷有序相。最近的实验表明，铜YBa2Cu3O7-δ的准粒子质量m*在接近最佳掺杂时显著增加，这表明电荷有序相的量子涨落可能是高tc超导性的原因。我们通过在静水压力下对化学计量化合物YBa2Cu4O8进行量子振荡研究，测试了m*和Tc之间相关性的稳健性。与YBa2Cu3O7-δ的结果相反，我们发现在压力下，YBa2Cu4O8的质量随着Tc的增加而减小。m*和Tc之间的负相关表明，电荷序的量子涨落增强了m*，但不增强Tc。
Contrary to what is expected near a quantum critical point, pressure decreases the quasiparticle mass of a high-Tc superconductor. Close to a zero-temperature transition between ordered and disordered electronic phases, quantum fluctuations can lead to a strong enhancement of electron mass and to the emergence of competing phases such as superconductivity. A correlation between the existence of such a quantum phase transition and superconductivity is quite well established in some heavy fermion and iron-based superconductors, and there have been suggestions that high-temperature superconductivity in copper-oxide materials (cuprates) may also be driven by the same mechanism. Close to optimal doping, where the superconducting transition temperature Tc is maximal in cuprates, two different phases are known to compete with superconductivity: a poorly understood pseudogap phase and a charge-ordered phase. Recent experiments have shown a strong increase in quasiparticle mass m* in the cuprate YBa2Cu3O7-δ as optimal doping is approached, suggesting that quantum fluctuations of the charge-ordered phase may be responsible for the high-Tc superconductivity. We have tested the robustness of this correlation between m* and Tc by performing quantum oscillation studies on the stoichiometric compound YBa2Cu4O8 under hydrostatic pressure. In contrast to the results for YBa2Cu3O7-δ, we find that in YBa2Cu4O8, the mass decreases as Tc increases under pressure. This inverse correlation between m* and Tc suggests that quantum fluctuations of the charge order enhance m* but do not enhance Tc.