2003/01/29 by K. K. Lee, A. S. Alexandrov, W. Y. Liang · 9 citations
Materials Science · Physics and Astronomy · #Bipolaron #Charge carrier #Cuprate #Electron #Excited state #Magnetic and transport properties of perovskites and related materials #Phonon #Physics of Superconductivity and Magnetism #Polaron #Superconductivity #Superconductivity in MgB2 and Alloys #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1140/epjb/e2004-00218-6
published in The European Physical Journal B 39(4), 459-468 (Springer Science+Business Media) · 9 pages, 6 figures. Submitted to Physical Review B
arxiv created 2003/01/29 · openalex publication_date 2004/06/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
With the superconducting cuprates in mind, a set of unitary transformations was used to decouple electrons and phonons in the strong-coupling limit. While phonons remain almost unrenormalised, electrons are transformed into itinerent singlet and triplet bipolarons and thermally excited polarons. The triplet/singlet exchange energy and the binding energy of the bipolarons are thought to account for the spin and charge pseudogaps in the cuprates, respectively. We calculated the Hall Lorenz number of the system to show that the Wiedemann-Franz law breaks down due to the interference of the polaron and bipolaron contributions to heat flow. The model provides a quantitative fit to magnetotransport data in the cuprates. Furthermore we are able to extract the phonon component of the thermal conductivity with the use of experimental data and the model. Our results further validate the use of a charged Bose gas model to describe normal and superconducting properties of unconventional superconductors.