Shaginyan V R, Stephanovich V A, Msezane A Z, Japaridze G S, Popov K G
Petersburg Nuclear Physics Institute, NRC "Kurchatov Institute", Gatchina, 188300, Russia.
Phys Chem Chem Phys. 2017 Aug 23;19(33):21964-21969. doi: 10.1039/c7cp02720f.
We show that a 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 LaSrCuO, whose superconductivity features differ from what is predicted by the classical Bardeen-Cooper-Schrieffer theory. This observation can open avenues for chemical preparation of high-T materials. We demonstrate that (1) at temperature T = 0, the superfluid density n turns out to be considerably smaller than the total electron density; (2) the critical temperature T is controlled by n rather than by doping, and is a linear function of the n; (3) at T > T the resistivity ρ(T) varies linearly with temperature, ρ(T) ∝ αT, where α diminishes with T → 0, whereas in the normal (non superconducting) region induced by overdoping, T = 0, and ρ(T) ∝ T. Our results are in good agreement with recent experimental observations.
我们表明，量子相变会产生平带并改变费米面拓扑结构，这是由LaSrCuO代表的过掺杂高温超导体出现奇异行为的主要原因，其超导特性不同于经典巴丁 - 库珀 - 施里弗理论的预测。这一发现可为高温材料的化学制备开辟途径。我们证明：（1）在温度T = 0时，超流密度n远小于总电子密度；（2）临界温度T由n而非掺杂控制，且是n的线性函数；（3）在T > T时，电阻率ρ(T)随温度线性变化，ρ(T) ∝ αT，其中α随T → 0而减小，而在过掺杂诱导的正常（非超导）区域，T = 0且ρ(T) ∝ T。我们的结果与最近的实验观测结果高度吻合。
