Electron-phonon interaction in the new superconductors<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mi mathvariant="normal">−</mml:mi><mml:mi mathvariant="normal">x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>(Ba,Sr<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mi mathvariant="normal">x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CuO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>
Аннотация
A realistic tight-binding theory, based on the first-principles energy-band results of Mattheiss, is used to study the electron-phonon interaction in the new high-${\mathrm{T}}_{\mathrm{c}}$ superconductors ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathrm{x}}$(Ba,Sr${)}_{\mathrm{x}}$${\mathrm{CuO}}_{4}$. The calculated results include the phonon dispersion curves, phonon linewidths, the Eliashberg function ${\mathrm{\ensuremath{\alpha}}}^{2}$(\ensuremath{\omega})F(\ensuremath{\omega}), and the interaction constant \ensuremath{\lambda}. A very strong couplin of specific O phonons to the conduction electrons is found (\ensuremath{\lambda}\ensuremath{\ge}2), leading---because of the light oxygen mass---to ${\mathrm{T}}_{\mathrm{c}}$ values of \ensuremath{\sim}30-40 K.
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