Phonon and magnon mediated d-wave superconductivity in cuprates

• Дата: 1996
• Автори: Sherman, A., Schreiber, M.
• Формат: Стаття
• Мова: English
• Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 1996
• Назва видання: Физика низких температур
• Теми: Специальный выпуск Международная конференция "Сверхпроводимость. Физические аспекты"
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/176058
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Phonon and magnon mediated d-wave superconductivity in cuprates / A. Sherman, M. Schreiber // Физика низких температур. — 1996. — Т. 22, № 5. — С. 503-505. — Бібліогр.: 12 назв. — англ.

We use the Eliashberg formalism for calculating Tc in the 2D t-J model supplemented by an interaction with fulJy-symmetric apex-oxygen vibrations. It is shown that in this model holes form an anomalous 2D Fermi liquid with a Fermi surface which is also two-dimensional in a certain range of hole concentrations x. This Fermi surface is a part of a large nearly flat region around the boundaries of the magnetic Brillouin zone. Extended saddle points, analogous to those observed in angle-resolved photoemission spectra, form the main part of this region. It produces a pronounced maximum in the density of states near the Fermi level. However, in spite of this favorable condition for superconductivity, created by the hole-magnon interaction, we found this interaction alone to be unable to yield high Tc . Only together with a moderate hole-phonon interaction does it lead to d-wave superconductivity at temperatures and hole concentrations observed in cuprates. High Tc are connected with a large density of states in the nearly flat region, a conformity of the two interactions for the dx²-y² symmetry, and a high phonon frequency Ω. The obtained dependences of Tc on x and on Ω are in close agreement with observations in cuprates. Remove selected