## Abstract

We analyze optical conductivity of a clean two-dimensional electron system in a Fermi liquid regime near a T=0 Ising-nematic quantum critical point (QCP) and extrapolate the results to a QCP. We employ direct perturbation theory up to the two-loop order to elucidate how the Fermi surface's geometry (convex vs concave) and fermionic dispersion (parabolic vs nonparabolic) affect the scaling of the optical conductivity σ(ω) with frequency ω and correlation length ζ. We find that for a convex Fermi surface the leading terms in the optical conductivity cancel out, leaving a subleading contribution σ(ω)∝ω2ζ4L, where L=const for a parabolic dispersion and L∝lnωζ3 in a generic case. For a concave Fermi surface, the leading terms do not cancel, and σ(ω)∝ζ2. We extrapolate these results to a QCP and obtain σ(ω)∝ω2/3 for a convex Fermi surface and σ(ω)∝1/ω2/3 for a concave Fermi surface.

Original language | English (US) |
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Article number | 115156 |

Journal | Physical Review B |

Volume | 109 |

Issue number | 11 |

DOIs | |

State | Published - Mar 15 2024 |

### Bibliographical note

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