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arXiv · 2302.04172

Non Fermi liquid behavior at flat hot spots from quantum critical fluctuations at the onset of charge- or spin-density wave order

Lukas Debbeler·Walter Metzner
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Abstract

We analyze quantum fluctuation effects at the onset of charge or spin density wave order with a $2k_F$ wave vector $\mathbf{Q}$ in two-dimensional metals -- for the special case where $\mathbf{Q}$ connects a pair of hot spots situated at high symmetry points of the Fermi surface with a vanishing Fermi surface curvature. We compute the order parameter susceptibility and the fermion self-energy in one-loop approximation. The susceptibility has a pronounced peak at $\mathbf{Q}$, and the self-energy displays non-Fermi liquid behavior at the hot spots, with a linear frequency dependence of its imaginary part. The real part of the one-loop self-energy exhibits logarithmic divergences with universal prefactors as a function of both frequency and momentum, which may be interpreted as perturbative signatures of power laws with universal anomalous dimensions. As a result, one obtains a non-Fermi liquid metal with a vanishing quasiparticle weight at the hot spots, and a renormalized dispersion relation with anomalous algebraic momentum dependencies near the hot spots.

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Lukas Debbeler, Walter Metzner. 2023-02-08. Non Fermi liquid behavior at flat hot spots from quantum critical fluctuations at the onset of charge- or spin-density wave order. https://doi.org/10.1103/physrevb.107.165152

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