Competing charge density-wave and superconducting states in a quasi-one dimensional two-band electron-phonon model

C. Bourbonnais; A. Ghosh; M. Haguier

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arXiv · 2610.05321

Competing charge density-wave and superconducting states in a quasi-one dimensional two-band electron-phonon model

C. Bourbonnais·A. Ghosh·M. Haguier

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Abstract

We apply the renormalization group method to examine the interplay between the charge density-wave and superconductivity phases in two quasi-one-dimensional tight-binding electronic bands coupled by the electron-phonon interaction. The electronic and phonon energy scales are embedded in a two-cutoff scaling scheme at finite temperature for the renormalization group flow equations of intra- and inter-band phonon-mediated interactions between electrons. At the one-loop level different regimes of renormalization are derived covering both the adiabatic and antiadiabatic domains for small and large phonon frequencies. Finite temperature phase diagrams as a function of nesting frustration of the electron spectrum are thus obtained. The possibilities for superimposed charge density-wave and superconducting ordered states are given. The emergence of domes of superconductivity resulting from quantum critical reinforcement of Cooper pairing by charge density-wave order fluctuations is found. The impact of the multiband character of the electronic structure on the ordering temperature of superconductivity, quantum criticality, and isotope effect is discussed.

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C. Bourbonnais, A. Ghosh, M. Haguier. 2026-10-04. Competing charge density-wave and superconducting states in a quasi-one dimensional two-band electron-phonon model. https://arxiv.org/abs/2610.05321

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