An alternative theory on relaxation rates in cuprate superconductors

Abstract

Transport properties of high transition temperature (high-T(c)) superconductors apparently demonstrate two distinct relaxation rates in the normal state. We propose that this superficial inconsistence can be resolved with an effective carrier (quasiparticle) density n almost linear in temperature T. Experimental evidence both for and against this explanation is analyzed and we conclude that this offers a clear yet promising scenario. Band structure calculation was utilized to determine the Fermi surface topology of the cuprate superconductor versus doping. The results demonstrate that an electron-like portion of the Fermi surface exists in a wide range of doping levels even for a p-type superconductor, exemplified by La(2-x)Sr(x)CuO(4-δ) (LSCO). Such electron-like segments have also been confirmed in recent photoemission electron spectroscopy. The Coulomb interaction between electron-like and hole-like quasiparticles then forms a bound state, similar to that of an exciton. As a result the number of charge carriers upon cooling temperature is decreased. A quantum mechanical calculation of scattering cross section demonstrates that a T(2) relaxation rate is born out of an electron-hole collision process. Above the pseudogap temperature T(*) the normal state of high-T(c) cuprates is close to a two-component Fermi liquid. It, however, assumes non-Fermi-liquid behavior below T(*).

Evidence for a universal Fermi-liquid scattering rate throughout the phase diagram of the copper-oxide superconductors

“…These and other experimental observations have been argued to be the result of an underlying quantum critical point at p * with associated fluctuations that give rise to the extended T-linear resistive behavior and to the superconductivity [1]. On the other hand, there also have been suggestions that, fundamentally, FL theory should prevail [4,[15][16][17][18][19], and that the consideration of electron interactions results in resistivity saturation values much larger than implied by the Ioffe-Regel condition, consistent with experiment [4,20]. In fact, there has been a recent revival of FL concepts in correlated systems in general, including considerations of a FL scattering rate that extends to high temperatures (appendix A).…”

Generalized gradient calculations of structural, electronic and optical properties of MgxCd1−xO oxides

“…The theory is widely used by the materials scientists [2][3][4][5][6][7][8][9] to study various physical properties such as relative stability, chemical bonding, relaxation of the atoms, phase transitions, electrical, mechanical, optical and magnetic properties of solid materials [10].…”

Компьютерное Моделирование Наноскопических Фазово-Неоднородных Состояний И Фазовых Диаграмм ВТСП Купратов И Никелатов

“…Отметим, что локальные средние фермионных операторов типа P ν ± и N ν ± были впервые использованы в приближении среднего поля Кэроном и Праттом (Caron and Pratt [18]) для описания модели Хаббарда в реальном координатном, а не импульсном, как обычно, представлении. Металлические P-и N-состояния взаимодействуют и смешиваются благодаря PN (NP) вкладам в одночастичный транспорт (3), что приводит к необычным свойствам металлических фаз купратов/никелатов со специфическим сосуществованием электронных и дырочных носителей в купратах как с дырочным, так и с электронным допированием [19,20]. Здесь мы упомянули самые простые " монофазы" с единственным отличным от нуля локальным параметром порядка.…”