摘要
Many issues concerning the origin of high-temperature superconductivity(HTS)are still under debate.For example,how the magnetic order varies with doping and its relationship with the superconducting temperature(Tc);and why Tcalways peaks near the quantum critical point.In this paper,taking hole-doped La_(2)CuO_(4)as a classical example,we employ the first-principles band structure and total energy calculations with Monte Carlo simulations to explore how the symmetry-breaking magnetic ground state evolves with hole doping and the origin of a dome-shaped superconductivity region in the phase diagram.We demonstrate that the local antiferromagnetic order and doping play key roles in determining the electron-phonon coupling,thus Tc.Initially,the La_(2)CuO_(4)possesses a checkerboard local antiferromagnetic ground state.As the hole doping increases,Tcincreases with the enhanced electron-phonon coupling strength.But as the doping increases further,the strength of the antiferromagnetic interaction weakens and spin fluctuation increases.At the critical doping level,a magnetic phase transition occurs that reduces the local antiferromagnetism-assisted electron-phonon coupling,thus diminishing the Tc.The superconductivity disappears in the heavily overdoped region when the ferromagnetic order dominates.These observations could account for why cuprates have a dome-shaped superconductivity region in the phase diagram.Our study,thus,contributes to a fundamental understanding of the correlation between doping,local magnetic order,and superconductivity of HTS.
基金
supported by the National Natural Science Foundation of China(Grant Nos.61922077,11874347,11991060,12088101,61927901
U2230402)
the National Key Research and Development Program of China(Grant Nos.2018YFB2200100,and 2020YFB1506400)
the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0460000)
the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-026)
supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.Y2021042)。