Strong doping dependence of the interlayer superconducting coherence in Bi2(Sr,La)2CaCu2O8+y

c-axis coupling in underdopedBi2Sr2CaCu2Spathis1, Colson2, Yang3 et al. 2008Phys. Rev. BSelf Cite4010View full textAdd to dashboardCite

“…39͒ and 0.11, 47 the evolution of which recalls the exponential f pl 2 ͑0͒͑T c ͒ dependence found by Shibauchi and Horiuchi. 16 The results are somewhat similar to those obtained by Fukuzumi et al for Zn-doped and oxygen-deficient YBa 2 Cu 3 O 7−␦ , 35 however, their Fig. 5 shows a linear dependence of f pl on T c for underdoped YBa 2 ͑Cu 1−x Zn x ͒ 3 O 6.63 , and a hyperbolic or exponential evolution of f pl ͑T c ͒ as function of ␦.…”

“…11 First, scanning tunneling spectroscopy experiments [12][13][14] have revealed large variations of the magnitude of the gap maximum ⌬ peak , as interpreted from conductance curves measured on the surface of Bi 2 Sr 2 CaCu 2 O 8+␦ crystals. This has motivated recent interpretations of weakened c-axis superfluid response in this material 15,16 as well as in La 2−x Sr x CuO 4 ͑Ref. 17͒ in terms of finely dispersed 5 -20-nm-sized nonsuperconducting regions within the CuO 2 planes.…”

“…54 It is interesting that the existence of a second small energy scale describing nodal quasiparticle excitations may well be responsible for the observed suppression of j c c as a function of doping ͑de-creasing p or ␦͒. 16 The proportionality of this decrease to the ratio of the gap maximum ͑at the antinode͒ and T c finds a logical explanation if the smaller energy scale ͓ϳ͑2 -2.5͒k B T c ͔ is what determines the magnitude of the c-axis critical current density. Thus, the ͑incoherent͒ interlayer assisted hopping is a feasible candidate for the reduction of the c-axis superfluid density in underdoped Bi 2 Sr 2 CaCu 2 O 8+␦ : it parametrically describes the data, and numerical values extracted for the relevant energy scale determining the quasiparticle excitations are the same as found in other experiments.…”

Nature of c-axis coupling in underdoped Bi2Sr2CaCu2O8 with varying degrees of disorder

“…The same Figure recapitulates results for doping levels p = 0.13 39 and 0.11, 47 the evolution of which recalls the exponential f 2 pl (0)(T c )-dependence found by Shibauchi et al. 16 The results are somewhat similar to those obtained by Fukuzumi et al for Zn-doped and oxygen-deficient YBa 2 Cu 3 O 7−δ : 35 however, their Fig. 5 shows a linear dependence of f pl on T c for underdoped YBa 2 (Cu 1−x Zn x ) 3 O 6.63 , and a hyperbolic or exponential evolution of f pl (T c ) as function of δ.…”

“…11 First, scanning tunneling spectroscopy (STS) experiments 12,13,14 have revealed large variations of the magnitude of the gap maximum ∆ peak , as interpreted from conductance curves measured on the surface of Bi 2 Sr 2 CaCu 2 O 8+δ crystals. This has motivated recent interpretations of weakened c-axis superfluid response in this material 15,16 as well as in La 2−x Sr x CuO 4 17 in terms of finely dispersed 5 -20 nm-sized non-superconducting regions within the CuO 2 planes. Such regions may arise from the suppression of the superconducting order parameter by dopant atoms, 18 such as out-of-plane oxygen atoms in the Bi 2 Sr 2 CaCu 2 O 8+δ compound.…”