Effects of the pseudo-gap on the field-induced kinetic energy density of Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ single crystals

Abstract

We report on magnetization experiments from which we obtain the field-induced kinetic energy density, E k , in the superconducting phase of several Bi2Sr2CaCu2O 8+δ single crystal samples. The kinetic energy magnitude changes according to the characteristic reduction of the single-electron density of states produced by the pseudogap in the underdoped limit. Moreover, a remarkable peak of E k occurring at the specific holes density p ∼ 0.18 is related to a van Hove singularity due to the pseudogap closure.We also extracted the superfluid density, ρs.We conclude that E k and ρs are related to the pseudogap energy scale. This result is understood as an evidence of the coexistence between superconductivity and the pseudogap phenomenon in the Bi2Sr2CaCu2O 8+δ cuprate compound.

Stripes in oxygen-enriched cuprates

“…33,48 For Bi-based cuprates with two CuO 2 planes per unit cell, such as Bi 2 Sr 2 CaCu 2 O 8+δ , the universal-dome method seems quite reliable and is widely used. [49][50][51] Conversely, the universal-dome method is not applicable to singleplane Bi 2 Sr 2−x Ln x CuO 6+δ (Ln = La, Bi), because of both oxygen enrichment and electron doping by Ln→Sr substitution. Instead, the carrier density is obtained from the size of the Fermi surface (Luttinger theorem).…”