Ab initio study of superconductivity and inhomogeneity in a Hg-based cuprate superconductor
Ab initio study of superconductivity and inhomogeneity in a Hg-based cuprate superconductor
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DOI：
10.1103/physrevb.101.045124
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发表时间：
2019-01
影响因子：
3.7
通讯作者：
Takahiro Ohgoe;M. Hirayama;Takahiro Misawa;Kota Ido;Y. Yamaji;M. Imada
中科院分区：
文献类型：
--
作者：
Takahiro Ohgoe;M. Hirayama;Takahiro Misawa;Kota Ido;Y. Yamaji;M. Imada
理解高T_c超导体的物理性质一直是材料科学中的重要问题之一。尽管许多不同的理论对超导电性和相互竞争的有序进行了争论，但对从头算和定量方面的理解还很欠缺。在这里，我们通过求解HgBa2$CuO4+y}的从头算低能有效哈密顿量来再现HgBa2$CuO4+y}的实验相图。它在很宽的空穴密度范围内显示出超导相，它与电荷周期-4加上自旋周期-8的条带序竞争在-β-sim 0.1$附近，这与包括最近的X射线散射在内的实验结果相一致。然后阐述了场外相互作用在稳定超导电性中的重要作用，并着重讨论了电荷涨落。并阐明了凝聚能主要来自现场库仑相互作用。这一成果将使我们能够对高T_c超导机制的公开问题有更深入、更可预测的理解，并推动对强关联电子的从头计算研究超越参数化模型研究。
Understanding physics of high-$T_c$ cuprate superconductors remains one of the important problems in materials science. Though a number of diverse theories argue about the superconductivity and competing orders, ab initio and quantitative understanding is lacking. Here, we reproduce the experimental phase diagram of HgBa$_2$CuO$_{4+y}$ by solving its ab initio low-energy effective Hamiltonian without adjustable parameters. It shows a superconducting phase in a wide range of hole density $\delta$, and its competition with charge period-4 plus spin period-8 stripe order near $\delta \sim 0.1$, in agreement with experimental results including recent X-ray scattering. Then a crucial role of off-site interactions in stabilizing the superconductivity is elucidated with emphasis on charge fluctuations. It also clarifies the condensation energy mainly contributed from the onsite Coulomb interaction. The present achievement will enable deeper, predictable understanding on open issues of the high-$T_c$ superconducting mechanism and promote ab initio studies on strongly correlated electrons beyond parametrized model studies.