Random strain induced correlations in materials with intertwined nematic and magnetic orders

W. Joe Meese, Thomas Vojta, Rafael M. Fernandes

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1 Scopus citations

Abstract

Electronic nematicity is rarely observed as an isolated instability of a correlated electron system. Instead, in iron pnictides and in certain cuprates and heavy-fermion materials, nematicity is intertwined with an underlying spin-stripe or charge-stripe state. As a result, random strain, ubiquitous in any real crystal, creates both random-field disorder for the nematic degrees of freedom and random-bond disorder for the spin or charge ones. Here, we put forward an Ashkin-Teller model with random Baxter fields to capture the dual role of random strain in nematic systems for which nematicity is a composite order arising from a stripe state. Using Monte Carlo to simulate this random Baxter-field model, we find not only the expected breakup of the system into nematic domains, but also the emergence of nontrivial disorder-promoted magnetic correlations. Such correlations enhance and tie up the fluctuations associated with the two degenerate magnetic stripe states from which nematicity arises, leaving characteristic signatures in the spatial profile of the magnetic domains, in the configurational space of the spin variables, and in the magnetic noise spectrum. We discuss possible experimental manifestations of these effects in iron-pnictide superconductors. Our work establishes the random Baxter-field model as a more complete alternative to the random-field Ising model to describe complex electronic nematic phenomena in the presence of disorder.

Original languageEnglish (US)
Article number115134
JournalPhysical Review B
Volume106
Issue number11
DOIs
StatePublished - Sep 15 2022

Bibliographical note

Funding Information:
We thank A. Chakraborty, J. Freedberg, and E. D. Dahlberg for fruitful discussions. W.J.M. and R.M.F. were supported by the U. S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under Award No. DE-SC0020045. T.V. was supported by the National Science Foundation under Grant No. DMR-1828489. T.V. and R.M.F. acknowledge the hospitality of KITP at UCSB, where the work was initiated. KITP is supported by the National Science Foundation under Grant No. NSF PHY-1748958. We thank the Minnesota Supercomputing Institute (MSI) at the University of Minnesota, where the numerical computations were performed.

Publisher Copyright:
© 2022 American Physical Society.

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