Correlation of the superconducting critical temperature with spin and orbital excitations in(CaxLa1−x)(Ba1.75−

Abstract

Electronic spin and orbital (dd) excitation spectra of (Ca x La 1−x )(Ba 1.75−x La 0.25+x )Cu 3 O y samples are measured by resonant inelastic x-ray scattering (RIXS). In this compound, T c of samples with identical hole dopings is strongly affected by the Ca/Ba substitution x due to subtle variations in the lattice constants, while crystal symmetry and disorder as measured by linewidths are x independent. We examine two extreme values of x and two extreme values of hole-doping content y corresponding to antiferromagnetic and superconducting states. The x dependence of the spin-mode energies is approximately the same for both the antiferromagnetic and superconducting samples. This clearly demonstrates that RIXS is sensitive to the superexchange J even in doped samples. A positive correlation between J and the maximum of T c at optimal doping (T max c ) is observed. We also measured the x dependence of the d xy → d x 2 −y 2 and d xz/yz → d x 2 −y 2 orbital splittings. We infer that the effect of the unresolved d 3z 2 −r 2 → d x 2 →y 2 excitation on T max c is much smaller than the effect of J . There appears to be dispersion in the d xy → d x 2 −y 2 peak of up to 0.05 eV. Our fitting furthermore indicates an asymmetric dispersion for the d xz/yz → d x 2 −y 2 excitation. A peak at ∼0.8 eV is also observed and attributed to a dd excitation in the chain layer.

Signatures of strong correlation effects in resonant inelastic x-ray scattering studies on cuprates

“…The other one is the paramagnonlike excitation the resonance peaks of which are located independently of the incident photon energy. However, from our calculations we find these two excitations all contribute to the spin susceptibility, which is consistent with the recent experiment [33]. They may have a dispersion similar to AFM spin waves at small momenta q, but they are mixed together.…”

Local and collective magnetism ofEuFe2As2

“…2(a) In recent years, RIXS has received a lot of attention due to the huge instrumental improvements in terms of both energy resolution and flux 58,59 permitting the detection of magnetic excitations in high temperature superconductors such as cuprates and Fe pnictides [40][41][42][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95] .…”

Electronic structure of the ingredient planes of the cuprate superconductorBi2Sr2CuO6+δ: A comparison study withBiLv1, Wang2, Ding3 et al. 2016Phys. Rev. B14160View full textAdd to dashboardCite

“…In bismuth-based cuprates, for example, T c, max is approximately 34 K, 90 K, and 110 K for n = 1, 2, 3, respectively 2 . It has led to numerous competing proposals to explain this intriguing phenomenon, which include interlayer quantum tunneling of Cooper pairs [3][4][5] , intralayer hopping 6 , the energy level of apical oxygen 7 , magnetic exchange interactions 8,9 , and so on. Thus far, however, a consensus on which factor controls T c in cuprate superconductors has not yet been reached, partially due to a lack of knowledge about the detailed electronic properties outside the superconducting CuO 2 planes, which are anti-ferromagnetic insulators without doping.…”