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arXiv · 1801.04885

Fluctuation effects at the onset of $\bf 2k_F$ density wave order with one pair of hot spots in two-dimensional metals

Jáchym Sýkora·Tobias Holder·Walter Metzner
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Abstract

We analyze quantum fluctuation effects at the onset of charge or spin density wave order in two-dimensional metals with an incommensurate $2k_F$ wave vector connecting a single pair of hot spots on the Fermi surface. We compute the momentum and frequency dependence of the fermion self-energy near the hot spots to leading order in a fluctuation expansion (one loop). Non-Fermi liquid behavior with anomalous frequency scaling and a vanishing quasi particle weight is obtained. The momentum dependence yields a divergent renormalization of the Fermi velocity and a flattening of the Fermi surface near the hot spots. Going beyond the leading order calculation we find that the one-loop result is not self-consistent. We show that any momentum-independent self-energy with a non-Fermi liquid frequency exponent wipes out the peak of the polarization function at the $2k_F$ wave vector, and thus destroys the mechanism favoring $2k_F$ density waves over those with generic wave vectors. However, a $2k_F$ density wave quantum critical point might survive in presence of a sufficiently flat renormalized Fermi surface.

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Jáchym Sýkora, Tobias Holder, Walter Metzner. 2018-11-14. Fluctuation effects at the onset of $\bf 2k_F$ density wave order with one pair of hot spots in two-dimensional metals. https://doi.org/10.1103/physrevb.97.155159

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