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Spin-fluctuation-driven B1g and B2g Bond Order and Induced In-plane Anisotropy in Magnetic Susceptibility in Cuprate Superconductors: Impact of Hot-/Cold-spot Structure on Bond-order Symmetry

K. Kawaguchi, S. Onari, and H. Kontani J. Phys. Soc. Jpn. 89, 124704 (2020).

Electronic nematic states in cuprate high-Tc superconductors are not only ubiquitous but also very diverse. Recently, a B1g-symmetry nematic transition around the pseudogap temperature T* has been reported in Y- and Bi-based compounds, whereas B2g-symmetry nematicity has been observed in Hg-based compounds. To understand the reason for the difference in the symmetry of nematicity, we examine the charge-channel density wave states in the d–p Hubbard model based on the spin-fluctuation mechanism, by considering not only the vertex corrections but also the self-energy (Σ) corrections. The former gives the spin-fluctuation-driven charge instabilities, and the latter introduces the hot-spot structure (or Fermi arc structure) on the Fermi surface. When the hot-spot structure is less prominent, the B1g nematicity is obtained robustly. In contrast, the instability of B2g nematicity becomes comparable to that of B1g nematicity when the hot-spot structure is prominent. In both symmetries, the origin of nematicity is bond order, which is the rotational symmetry breaking in the self-energy-driven hopping integrals. In addition, we show that the bond orders induce in-plane anisotropy in magnetic susceptibility due to d,p-orbital angular momenta. Therefore, the symmetry of bond order can be determined by magnetic torque measurement. The present study gives insights into the diverse nematicities in cuprate superconductors.

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