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arXiv · 2310.07768

Tunable non-Fermi liquid phase from coupling to two-level systems

Noga Bashan·Evyatar Tulipman·Jörg Schmalian·Erez Berg
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Abstract

We study a controlled large-$N$ theory of electrons coupled to dynamical two-level systems (TLSs) via spatially-random interactions. Such a physical situation arises when electrons scatter off low-energy excitations in a metallic glass, such as a charge or stripe glass. Our theory is governed by a non-Gaussian saddle point, which maps to the celebrated spin-boson model. By tuning the coupling strength we find that the model crosses over from a Fermi liquid at weak coupling to an extended region of non-Fermi liquid behavior at strong coupling, and realizes a marginal Fermi liquid at the crossover. Beyond a critical coupling strength, the TLSs freeze and Fermi-liquid behavior is restored. Our results are valid for generic space dimensions $d>1$.

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Noga Bashan, Evyatar Tulipman, Jörg Schmalian, Erez Berg. 2023-10-11. Tunable non-Fermi liquid phase from coupling to two-level systems. https://doi.org/10.1103/physrevlett.132.236501

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