Possibilities for enhanced electron-phonon interactions and high-$T_c$ superconductivity in engineered bimetallic nano-structured superlattices

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Main Authors: Mandal, Shinjan, Soundararajan, Shrihari, Jain, Manish, Krishnamurthy, H. R.
Format: Preprint
Published: 2024
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_version_ 1866909610688905216
author Mandal, Shinjan
Soundararajan, Shrihari
Jain, Manish
Krishnamurthy, H. R.
author_facet Mandal, Shinjan
Soundararajan, Shrihari
Jain, Manish
Krishnamurthy, H. R.
contents We explore theoretically the properties of engineered bimetallic nano-structured superlattices where an array of nano-clusters of a simple (single band) metal are embedded periodically inside another simple metal with a different work function. The exploration is done using a simplified tight-binding model with Coulomb interactions included, as well as density functional theory. Taking arrays of "Ag" clusters of fixed sizes and configurations (when unrelaxed) embedded periodically in an "Au" matrix as an example, we show that a significant enhancement of electron-phonon interactions ensues, implying possibilities for high-$T_c$ superconductivity. The enhancement stems from a strong coupling, via Coulomb interactions, between the dipolar charge distribution that forms at the Au-Ag interfaces and the breathing and other modes of vibration of the light Ag atoms caged inside the heavier Au matrix. The interface dipoles form because of the interplay between the mismatch of the local potential seen by the conduction electrons localised in Wannier orbitals at the Ag and Au sites (the Ag sites being slightly repulsive relative to the Au sites) and the (long-range) Coulomb repulsion between electrons occupying these Wannier orbitals. We also discuss the DC transport in such systems.
format Preprint
id arxiv_https___arxiv_org_abs_2408_15820
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Possibilities for enhanced electron-phonon interactions and high-$T_c$ superconductivity in engineered bimetallic nano-structured superlattices
Mandal, Shinjan
Soundararajan, Shrihari
Jain, Manish
Krishnamurthy, H. R.
Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
Superconductivity
We explore theoretically the properties of engineered bimetallic nano-structured superlattices where an array of nano-clusters of a simple (single band) metal are embedded periodically inside another simple metal with a different work function. The exploration is done using a simplified tight-binding model with Coulomb interactions included, as well as density functional theory. Taking arrays of "Ag" clusters of fixed sizes and configurations (when unrelaxed) embedded periodically in an "Au" matrix as an example, we show that a significant enhancement of electron-phonon interactions ensues, implying possibilities for high-$T_c$ superconductivity. The enhancement stems from a strong coupling, via Coulomb interactions, between the dipolar charge distribution that forms at the Au-Ag interfaces and the breathing and other modes of vibration of the light Ag atoms caged inside the heavier Au matrix. The interface dipoles form because of the interplay between the mismatch of the local potential seen by the conduction electrons localised in Wannier orbitals at the Ag and Au sites (the Ag sites being slightly repulsive relative to the Au sites) and the (long-range) Coulomb repulsion between electrons occupying these Wannier orbitals. We also discuss the DC transport in such systems.
title Possibilities for enhanced electron-phonon interactions and high-$T_c$ superconductivity in engineered bimetallic nano-structured superlattices
topic Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2408.15820