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Investigation of A1g phonons in YBa2Cu3O7 by means of LAPW atomic-force calculations

R. Kouba·C. Ambrosch-Draxl
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Abstract

We report first-principles frozen-phonon calculations for the determination of the force-free geometry and the dynamical matrix of the five Raman-active A1g modes in YBa2Cu3O7. To establish the shape of the phonon potentials atomic forces are calculated within the LAPW method. Two different schemes - the local density approximation (LDA) and a generalized gradient approximation (GGA) - are employed for the treatment of electronic exchange and correlation effects. We find that in the case of LDA the resulting phonon frequencies show a deviation from experimental values of approximately -10%. Invoking GGA the frequency values are significantly improved and also the eigenvectors are in very good agreement with experimental findings.

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R. Kouba, C. Ambrosch-Draxl. 1997-07-11. Investigation of A1g phonons in YBa2Cu3O7 by means of LAPW atomic-force calculations. https://doi.org/10.1103/physrevb.56.14766

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