Multilayer Effects in Bi2Sr2Ca2Cu3O10+z Superconductors

TL;DR

This paper investigates the unique multilayer effects in Bi2Sr2Ca2Cu3O10+z superconductors, revealing how interlayer coupling and pseudogap interactions influence their high critical temperature and large superconducting gaps.

Contribution

It provides experimental evidence of distinct superconducting gaps in triple-layer cuprates and highlights the role of interlayer coupling and pseudogap effects in their superconducting properties.

Findings

Distinct superconducting gaps on inner and outer Cu-O2 layers

Interlayer coupling influences the high Tc and large gap ratio

Pseudogap effects significantly impact the electronic properties

Abstract

We discuss the characteristic features of triple Cu-O2 layer cuprates superconductors, by comparing those of single and double layer cuprates superconductors. After a brief introduction to multilayer cuprates and their characteristic properties such as the doping imbalance between the inner and outer Cu-O2 planes (IP and OP, respectively) revealed by nuclear magnetic resonance, we present the experimental results of angle resolved photoemission and Raman scattering spectroscopy for the triple layer Bi2Sr2Ca2Cu3O10+z which showed two different superconducting gaps opening on the IP and OP. The doping dependence of the double peak structure in Raman spectra was found to be qualitatively consistent with that of single and double layer cuprates, if each layer doping for the IP and OP is taken into account. The fact that the IP and OP share the same electronic phase diagram and the same transition temperature (Tc) hints to a coupling between the IP and OP. Moreover, the energies of IP and OP Raman peaks were found to be very large, not scaling with Tc, which can be attributed to the strong influence of the pseudogap of the underdoped IP in triple layer cuprates. These findings suggest that the high Tc and the large gap ratio of triple layer cuprates are realized through a combination of the interlayer coupling between the OP and IP and the interaction between superconductivity and the pseudogap.