Orbital order in FeSe: The case for vertex renormalization

Journal Article · 23 July 2018 · Physical Review B

DOI: https://doi.org/10.1103/PhysRevB.98.041108 · OSTI ID:1466620

Xing, Rui-Qi ^[1]; Classen, Laura ^[2]; Chubukov, Andrey V. ^[1]

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1. Univ. of Minnesota, Minneapolis, MN (United States)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)

We study the structure of the orbital order Γ = ^†_xzd_xz - d^†_yzd_yz> in FeSe in light of recent scanning tunneling microscopy and angle-resolved photoemission spectroscopy (ARPES) data, which detect the shapes of the hole and electron pockets in the nematic phase. The geometry of the pockets indicates that the sign of Γ is different between the hole and electron pockets (Γ_h and Γ_e). We argue that this sign change cannot be reproduced if one solves for the orbital order within the mean-field approximation, as the mean-field analysis yields either no orbital order, or order with the same sign of Γ_e and Γh. We argue that another solution with the opposite signs of Γ_e and Γ_h emerges if we include the renormalizations of the vertices in the d -wave orbital channel. We show that the ratio |Γ_e/Γ_h| is of order one, independent of the strength of the interaction. We also compute the temperature variation of the energy of d_xz and d_yz orbitals at the center of electron pockets and compare the results with ARPES data.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: SC0012704
• OSTI ID: 1466620
• Alternate ID(s): OSTI ID: 1461574
• Report Number(s): BNL--207975-2018-JAAM
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 4 Vol. 98; ISSN 2469-9950; ISSN PRBMDO
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English