Pseudogap in high-temperature superconductors from realistic Fröhlich and Coulomb interactions

Abstract

It has been recently shown that the competition between unscreened Coulomb and Fröhlich electron-phonon interactions can be described in terms of a short-range spin exchange Jp and an effective on-site interaction Ũ in the framework of the polaronic t-Jp-Ũ model. This model, that provides an explanation for high temperature superconductivity in terms of Bose-Einstein condensation (BEC) of small and light bipolarons, is now studied as a charged Bose-Fermi mixture. Within this approximation, we show that a gap between bipolaron and unpaired polaron bands results in a strong suppression of low-temperature spin susceptibility, specific heat and tunneling conductance, signaling the presence of normal state pseudogap without any assumptions on preexisting orders or broken symmetries in the normal state of the model.

Polaron model of a pseudogap state in quasi-one-dimensional systems

“…Besides q1D-compounds, the pseudogap effects are observed in manganites with colossal magnetoresistance and high-temperature superconducting cuprates. Understanding the nature of this phenomenon within the framework of the polaron approach remains a topic of constant discussions [40][41][42][43][44][45][46][47].…”

ПОЛЯРОННАЯ МОДЕЛЬ ПСЕВДОЩЕЛЕВОГО СОСТОЯНИЯ В КВАЗИОДНОМЕРНЫХ СИСТЕМАХ, "Журнал Экспериментальной И Теоретической Физики"

“…Кроме q1D-соединений, псевдощелевые эффекты наблюдаются в манганитах с колоссальным магнитосопротивлением и ВТСП-купратах. Понимание природы этого явления в рамках поляронного подхода остается темой постоянных обсуждений [50][51][52][53][54][55][56][57]. В нашей работе приведен теоретический расчет, подтверждающий утверждения, сделанные выше.…”