Quantum oscillations from the reconstructed Fermi surface in electron-doped cuprate superconductors

J S Higgins,R L Greene,M K Chan,Tarapada Sarkar,N P Butch,R D Mcdonald

doi:10.1088/1367-2630/aab7e7

Abstract

We have studied the electronic structure of electron-doped cuprate superconductors via measurements of high-field Shubnikov–de Haas oscillations in thin films. In optimally doped Pr2−xCexCuO4±δ and La2−xCexCuO4±δ, quantum oscillations indicate the presence of a small Fermi surface, demonstrating that electronic reconstruction is a general feature of the electron-doped cuprates, despite the location of the superconducting dome at very different doping levels. Negative high-field magnetoresistance is correlated with an anomalous low-temperature change in scattering that modifies the amplitude of quantum oscillations. This behavior is consistent with effects attributed to spin fluctuations.

Highlights

The fundamentals of the electronic interactions in the copper oxide family of superconductors remain a subject of intense debate
Pr2−xCexCuO4±δ and La2−xCexCuO4±δ, quantum oscillations indicate the presence of a small Fermi surface, demonstrating that electronic reconstruction is a general feature of the electron-doped cuprates, despite the location of the superconducting dome at very different doping levels
To understand how the choice of rare earth element affects the Fermi surface (FS), we report here measurements of quantum oscillations in thin films of PCCO for x < xc and x > xc and in optimally doped LCCO, which can only be stabilized in film form [22, 23]

Summary

Introduction

The fundamentals of the electronic interactions in the copper oxide family of superconductors (cuprates) remain a subject of intense debate. One open question of particular importance is the nature of the normal state from which superconductivity emerges—whether it resembles a metal, having well-defined electron-like excitations, or a more exotic electronic phase. In hole-doped cuprates, the presence of a ‘pseudogap’ phase leads to even more uncertainty about the nature of the normal state. A schematic superconducting phase diagram for the electron-doped cuprates is shown in figure 1(a). The value of x for which the superconducting transition Tc is maximum is xo = 0.11 for La, 0.145 for Nd, and 0.15 for Pr. The actual cerium concentrations that determine the superconducting dome vary among the electron-doped cuprates, the general shape of the phase diagram is constant [6]

Methods

Results

Conclusion