Tuning superconductivity and charge density wave order by next-nearest-neighbor hopping integral in honeycomb Holstein model

Hongxing Liu; Lufeng Zhang; Tianxing Ma

doi:10.1103/nsr6-w9kj

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Tuning superconductivity and charge density wave order by next-nearest-neighbor hopping integral in honeycomb Holstein model

Hongxing Liu, Lufeng Zhang, Tianxing Ma

DOI 10.1103/nsr6-w9kj · Physical Review B

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Abstract

By using unbiased determinant quantum Monte Carlo simulations, we investigate the interplay between superconductivity and charge density wave order in the Holstein model on a honeycomb lattice with next-nearest-neighbor hopping t′. We find that a finite negative t′ enhances s-wave superconducting pairing susceptibility near the van Hove fillings in the weak electron-phonon coupling regime, while it suppresses superconductivity and promotes charge density wave order at intermediate electron-phonon coupling strengths. The effect of t′ on a charge density wave is filling dependent: it suppresses the charge density wave at half filling but enhances it near the van Hove singularities. A Spectral analysis reveals the opening of a gap at low temperatures, highlighting the competitive relationship between superconducting and charge density wave orders mediated by electron-phonon coupling and tuned by t′.