Phonon-mediated electron attraction in SrTiO$_3$ via the generalized Fröhlich and deformation potential mechanisms

Superconductivity in doped SrTiO$_3$ was discovered in 1964, the first superconducting transition observed in a doped semiconductor. However, the mechanism of electron pairing in SrTiO$_3$ remains a subject of debate. By developing a theoretical framework to incorporate dynamical lattice screening i...

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Main Authors Coveney, Christopher J. N, Tubman, Norm M, Hsu, Chih-En, Montoya-Castillo, Andres, Filip, Marina R, Neaton, Jeffrey B, Li, Zhenglu, Vlcek, Vojtech, Alvertis, Antonios M
Format Journal Article
LanguageEnglish
Published 28.01.2025
Subjects
Physics - Materials Science
Physics - Strongly Correlated Electrons
Physics - Superconductivity
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DOI10.48550/arxiv.2501.17230

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Summary:Superconductivity in doped SrTiO$_3$ was discovered in 1964, the first superconducting transition observed in a doped semiconductor. However, the mechanism of electron pairing in SrTiO$_3$ remains a subject of debate. By developing a theoretical framework to incorporate dynamical lattice screening in the electronic Coulomb interactions of semiconductors and insulators, we demonstrate analytically that linear long-range coupling of electrons to multiple longitudinal optical phonons, described by a generalized Fröhlich mechanism, can result in superconductivity in SrTiO$_3$. Moreover, by combining our theory with first-principles calculations, we reveal an additional attractive interaction between electrons in SrTiO$_3$ due to the deformation potential mechanism, arising from the mixed ionic-covalent character of the Ti-O bond. Our results may have implications for the emergence of phonon-mediated electron attraction and superconductivity in a broad range of materials.
DOI:10.48550/arxiv.2501.17230