Location and thermal evolution of the pseudogap due to spin fluctuations

Journal Article · Tue Sep 26 00:00:00 EDT 2023 · Physical Review. B

DOI:https://doi.org/10.1103/physrevb.108.115156· OSTI ID:2007062

Ye, Mengxing ^[1]; Wang, Zhentao ^[2]; Fernandes, Rafael M. ^[3]; Chubukov, Andrey V.  ^[3]

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1. University of California, Santa Barbara, CA (United States); University of Utah, Salt Lake City, UT (United States)
2. University of Minnesota, Minneapolis, MN (United States); Zhejiang University, Hangzhou (China)
3. University of Minnesota, Minneapolis, MN (United States)

We study pseudogap behavior in a metal near a spin density wave (SDW) instability due to thermal magnetic fluctuations. We consider the t–t' Hubbard model on a square lattice at a finite doping, at intermediate coupling strength, and analyze the thermal evolution of the electron spectral function between a SDW ordered state at low temperatures and a normal Fermi liquid at high temperatures. We argue that for proper description of the pseudogap one needs to sum up infinite series of diagrams for both the fermionic self-energy and the SDW order parameter in the SDW state or the magnetic correlation length in the paramagnetic state. We use the eikonal approach to sum up an infinite series of diagrammatic contributions from thermal fluctuations. Earlier studies found that in the SDW state the spectral function A_k(ω) of a hot fermion at a finite T is exponentially small below the energy scale Δ(T), which scales with SDW order and vanishes at the ordering temperature T_N, and has a hump at a larger frequency Δ_PG, comparable to the zero-temperature SDW gap Δ(T = 0). We argue that the hump, which we associate with the pseudogap, survives in some T range above T_N. We show that this range is split by regions of strong and weak pseudogap behavior. In the first region, Δ_PG is weakly temperature dependent, despite the fact that it comes from thermal fluctuations. Such a behavior has been seen in numerical studies of the Hubbard model. We show that to obtain it one needs to go beyond the one-loop approximation and sum up the infinite series of diagrams. In the second regime, Δ_PG decreases with increasing T and eventually vanishes. Here, we further argue that a magnetic pseudogap at a finite T emerges only if the ground state is magnetically ordered. We present the phase diagram and apply the results to high-T_c cuprates.

• Research Organization: Univ. of Minnesota, Minneapolis, MN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF); Gordon and Betty Moore Foundation; Simons Foundation
• Grant/Contract Number: SC0014402; SC0016371; PHY-1748958; GBMF8690; 216179; SC-0016371
• OSTI ID: 2007062
• Alternate ID(s): OSTI ID: 2006544
• Journal Information: Physical Review. B, Vol. 108, Issue 11; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
Superconductivity
Non-Fermi liquid
Exotic phases of matter
Magnetic susceptibility
Phase transitions
Quantum phase transitions