High-$T_c$ superconductors as a New Playground for High-order Van Hove singularities and Flat-band Physics

Robert S. Markiewicz; Bahadur Singh; Christopher Lane; Arun Bansil

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arXiv · 2303.08247

High-$T_c$ superconductors as a New Playground for High-order Van Hove singularities and Flat-band Physics

Robert S. Markiewicz·Bahadur Singh·Christopher Lane·Arun Bansil

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Abstract

Beyond the two-dimensional (2D) saddle-point Van Hove singularities (VHSs) with logarithmic divergences in the density of states (DOS), recent studies have identified higher-order VHSs with faster-than-logarithmic divergences that can amplify electron correlation effects. Here we show that the cuprate high-Tc superconductors harbor high-order VHSs in their electronic spectra and unveil a new correlation that the cuprates with high-order VHSs display higher Tc. Our analysis indicates that the normal and higher-order VHSs can provide a straightforward new marker for identifying propensity of a material toward the occurrence of correlated phases such as excitonic insulators and supermetals. Our study opens up a new materials playground for exploring the interplay between high-order VHSs, superconducting transition temperatures and electron correlation effects in the cuprates and related high-Tc superconductors.

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Robert S. Markiewicz, Bahadur Singh, Christopher Lane, Arun Bansil. 2023-03-14. High-$T_c$ superconductors as a New Playground for High-order Van Hove singularities and Flat-band Physics. https://arxiv.org/abs/2303.08247

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