Quantized Repetitions of the Cuprate Pseudogap Line

Abstract

The cuprate superconductors display several characteristic temperatures which decrease as the material composition is doped, tracing lines across the temperature-doping phase diagram. Foremost among these is the pseudogap transition. At a higher temperature a peak is seen in the magnetic susceptibility, and changes in symmetry and in transport are seen at other characteristic temperatures. We report a meta-analysis of all measurements of characteristic temperatures well above Tc in strontium doped lanthanum cuprate (LSCO) and oxygen doped YBCO. The experimental corpus shows that the pseudogap line is one of a family of four straight lines which stretches across the phase diagram from low to high doping, and from Tc up to 700 K. These lines all originate from a single point near the overdoped limit of the superconducting phase and increase as doping is reduced. The slope of the pseudogap lines is quantized, with the second, third, and fourth lines having slopes that are respectively 1/2, 1/3, and 1/4 of the slope of the highest line. This pattern suggests that the cuprates host a single mother phase controlled by a 2-D sheet density which is largest at zero doping and which decreases linearly with hole density, and that the pseudogap lines, charge density wave order, and superconductivity are all subsidiary effects supported by the mother phase.

Effective-Field Theory for Model High-Tc Cuprates

“…It should be noted that the PS model does predict several temperatures of the "third order" PS transitions limiting the PS phases, that is delineating areas with 100% volume fraction, and the temperatures of the percolation transitions, which can manifest itself in the peculiarities of the temperature behavior for different physical quantities [28]. All the phases AFMI, CO, and BS are separated from the 100% coherent metallic Fermi liquid phase by the "third order" phase transition line T (p), which is believed to be responsible for the onset of the pseudogap phenomena as a main candidate for the upper "pseudogap" temperature.…”

Indications for Topological Physics in High-$T_c$ Materials

“…This author recently performed a comprehensive survey of all experimental reports of characteristic temperatures well above the superconducting transition T c in strontium doped lanthanum cuprate (LSCO) and oxygen doped YBCO. 33 We report only characteristic temperatures at which clearly identifiable signals occur, for example opening of a pseudogap, peaks or kinks in the temperature dependence of various observables, or extinction of a diffraction peak at a particular temperature. These characteristic temperatures have been found using a wide variety of measurement techniques over a period of about three decades.…”

“…Ref. 33 Appendix reports six experimental temperature data sets that rise linearly with hole sheet density. Five of these extrapolate to T = 0 near the underdoped limit of the superconducting dome, i.e.…”

Природа Псевдощелевой Фазы ВТСП Купратов

“…главной" среди которых считается температура псевдощели T * , однако и при более высокой температуре наблюдается пик магнитной восприимчивости, а изменения симметрии и транспортных свойств наблюдаются и при меньших характерных температурах. Анализ характерных темпера-тур в купратах 214 и 123 [2] показывает, что зависимость T * (p) является всего лишь одной из семейства четырех почти прямых линий T n (p), которые простираются по широкой области фазовой диаграммы от низкого до высокого легирования и от T c до ∼ 700 K. Все эти линии сходятся в одной точке вблизи верхнего предела T c (p) сверхпроводимости и растут по мере уменьшения допирования. Наклон линий T n (p) " квантуется", причем вторая, третья и четвертая линии имеют наклоны, которые составляют соответственно 1/2, 1/3 и 1/4 от наклона самой высокой линии.…”

“…Наклон линий T n (p) " квантуется", причем вторая, третья и четвертая линии имеют наклоны, которые составляют соответственно 1/2, 1/3 и 1/4 от наклона самой высокой линии. Автор [2] полагает, что купраты содержат некую материнскую фазу, контролируемую плотностью заряда в плоскостях CuO 2 , а псевдощелевое поведение, волны зарядовой плотности и сверхпроводимость являются внешними проявлениями этой материнской фазы.…”