Bermes, Pit and Bohrdt, Annabelle and Grusdt, Fabian (2024) Magnetic polarons beyond linear spin-wave theory: Mesons dressed by magnons. PHYSICAL REVIEW B, 109 (20): 205104. ISSN 2469-9950, 2469-9969
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When a mobile hole is doped into an antiferromagnet, its movement will distort the surrounding magnetic order and yield a magnetic polaron. The resulting complex interplay of spin and charge degrees of freedom gives rise to very rich physics and is widely believed to be at the heart of high -temperature superconductivity in cuprates. In this paper, we develop a quantitative theoretical formalism, based on the phenomenological parton description, to describe magnetic polarons in the strong -coupling regime. We construct an effective Hamiltonian with weak coupling to the spin -wave excitations in the background, making the use of standard polaronic methods possible. Our starting point is a single hole doped into an antiferromagnet described by a "geometric string" capturing the strongly correlated hopping processes of charge and spin degrees of freedom, beyond linear spin -wave approximation. Subsequently, we introduce magnon excitations through a generalized 1 / S expansion and derive an effective coupling of these spin waves to the hole plus the string (the meson) to arrive at an effective polaron Hamiltonian with density -density type interactions. After making a Born-Oppenheimer-type approximation, this system is solved using the self -consistent Born approximation to extract the renormalized polaron properties. We apply our formalism (i) to calculate beyond linear spin -wave angle -resolved photoemission spectroscopy spectra, (ii) to reveal the interplay of rovibrational meson excitations, and (iii) to analyze the pseudogap expected at low doping. Moreover, our work paves the way for exploring magnetic polarons out of equilibrium or in frustrated systems, where weak -coupling approaches are desirable and going beyond linear spin -wave theory becomes necessary.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | HIGH-TC SUPERCONDUCTIVITY; HOLE DYNAMICS; SINGLE-HOLE; J MODEL; ANTIFERROMAGNET; MOTION |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics > Chair Professor Grifoni > Group Milena Grifoni |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 09 Dec 2025 09:53 |
| Last Modified: | 09 Dec 2025 09:53 |
| URI: | https://pred.uni-regensburg.de/id/eprint/65112 |
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