Possibility of Pomeranchuk instability in staggered flux state
Possibility of Pomeranchuk instability in staggered flux state
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DOI：
10.1088/1742-6596/1590/1/012017
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
Kenji K. Kobayashi;H. Yokoyama
中科院分区：
文献类型：
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作者：
Kenji K. Kobayashi;H. Yokoyama
结合铜超导体中的对称性破缺现象，用变分蒙特卡罗方法研究了具有次近邻转移t '的方形晶格上的强相关Hubbard模型（U/t = 12）在x - y和(x + y) - (x - y)各向异性（Pomeranchuk instability）上的不稳定性。作为变分函数，考虑了铜酸盐赝隙态的候选交错通量态ΨSF。ΨSF稳定在欠掺杂状态，并减少到正常状态（投影费米海）较大的掺杂区域。通过对ΨSF （t′/t = 0，±0.3）的分析，我们认为在x - y各向异性中，Pomeranchuk不稳定性的出现仅限于t′/t = 0和0.08≤δ≤0.20 （σ：掺杂率）的正常状态。由于强相关性引起的带重整效应（费米表面修饰）在论证中起着至关重要的作用。
In connection with the symmetry-breaking phenomena found in cuprate superconductors, the instability toward x−y and (x + y)−(x − y) anisotropy (Pomeranchuk instability) is studied for a strongly correlated Hubbard model (U/t = 12) on a square lattice with the next-nearest-neighbor transfer t′ using a variational Monte Carlo method. As a variational function, a staggered flux state ΨSF is considered, which is a candidate for the pseudogap state in cuprates. ΨSF is stabilized in a underdoped regime and reduced to the normal state (projected Fermi sea) for larger doping area. By analyzing ΨSF for t′/t = 0, ±0.3, we argue that the appearance of Pomeranchuk instability is limited to the normal state with t′/t = 0 and 0.08≤δ≤0.20 (σ: doping rate) in the x−y anisotropy. Band-renormalization effects (Fermi-surface modification) owing to strong correlations play a crucial role for the argument.