论文标题
在铜塔超导体中没有BCS-BEC跨界
Absence of a BCS-BEC crossover in the cuprate superconductors
论文作者
论文摘要
我们研究了Bardeen-Cooper-Schrieffer（BCS）对Bose-Einstein凝结（BEC）跨界的关键方面，重点是化学势的温度依赖性$μ$。我们确定了一种确定铜酸盐高温超导体从角度分辨 - 光发射数据（沿“鼻子”方向）的变化的准确方法，并表明$μ$在从低于几次的高于远低于超过的超级电压过度温度的温度下的温度下，$μ$的变化少于Fermi能量。这明确表明，这些材料不仅始终在交叉的BCS侧（这是在$ d-Wave案例中的相变），而且还远不及交叉点（化学电位接近频带底部）。
We examine key aspects of the theory of the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) crossover, focusing on the temperature dependence of the chemical potential, $μ$. We identify an accurate method of determining the change of $μ$ in the cuprate high temperature superconductors from angle-resolved-photoemission data (along the "nodal" direction), and show that $μ$ varies by less than a few percent of the Fermi energy over a range of temperatures from far below to several times above the superconducting transition temperature, $T_c$. This shows, unambiguously, that not only are these materials always on the BCS side of the crossover (which is a phase transition in the $d-wave case), but are nowhere near the point of the crossover (where the chemical potential approaches the band bottom).
