arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1702.05804cond-mat.supr-concond-mat.str-el
收藏

拓扑相变对过掺杂铜氧化物超流密度的影响

The influence of topological phase transition on the superfluid density of overdoped copper oxides

V. R. Shaginyan, V. A. Stephanovich, A. Z. Msezane, G. S. Japaridze, K. G. Popov

摘要:

我们表明,拓扑量子相变,产生平带和改变费米表面拓扑结构,是由$\rm La_{2-x}Sr_xCuO_4$代表的过掺杂高温超导体的奇异行为的主要原因,其超导特性不同于经典的Bardeen-Cooper-Schrieffer理论[J.I. Bozović,X. He,J. Wu,and A. T. Bollinger,Nature 536,309(2016)]。结果表明:1)在温度$T=0$下,超流密度$n_s$远小于总电子密度,2)临界温度$T_c$是由$n_s$控制的,而不是由掺杂控制的,并且是$n_s$的线性函数; 3)在$T>T_c$下,电阻率$ρ(T)$随温度线性变化,$ρ(T)\propto αT$,其中$α$随$T_c\to 0$减小,而在具有$T_c=0$的正常过掺杂(非超导)区域中,电阻率变为$ρ(T)\propto T^2$。提出的理论结果与最近的实验观察结果吻合良好,缩小了这些经验发现与Bardeen-Cooper-Schrifford理论之间的巨大差距。

英文摘要:

We show that a topological quantum phase transition, generating flat bands and altering Fermi surface topology, is a primary reason for the exotic behavior of the overdoped high-temperature superconductors represented by $\rm La_{2-x}Sr_xCuO_4$, whose superconductivity features differ from what is described by the classical Bardeen-Cooper-Schrieffer theory [J.I. Bozović, X. He, J. Wu, and A. T. Bollinger, Nature 536, 309 (2016)]. We demonstrate that 1) at temperature $T=0$, the superfluid density $n_s$ turns out to be considerably smaller than the total electron density; 2) the critical temperature $T_c$ is controlled by $n_s$ rather than by doping, and is a linear function of the $n_s$; 3) at $T>T_c$ the resistivity $ρ(T)$ varies linearly with temperature, $ρ(T)\propto αT$, where $α$ diminishes with $T_c\to 0$, while in the normal overdoped (non superconducting) region with $T_c=0$, the resistivity becomes $ρ(T)\propto T^2$. The theoretical results presented are in good agreement with recent experimental observations, closing the colossal gap between these empirical findings and Bardeen-Cooper-Schrieffer-like theories.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑