The effect of strain and pressure on the electron-phonon coupling and superconductivity in MgB2-Benchmark of theoretical methodologies and outlook for nanostructure design

• Different theoretical methodologies are employed to investigate the effect of hydrostatic pressure and anisotropic stress and strain on the superconducting transition temperature ( T-c) of MgB2. This is done both by studying Kohn anomalies in the phonon dispersions alone and by explicit calculation of the electron-phonon coupling. It is found that increasing pressure suppresses T-c in all cases, whereas isotropic and anisotropic strain enhances the superconductivity. In contrast to trialed epitaxial growth that is limited in the amount of achievable lattice strain, we propose a different path by co-deposition with ternary diborides that thermodynamically avoid mixing with MgB2. This is suggested to promote columnar growth that can introduce strain in all directions.

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NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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