Understanding electron-doped cuprate superconductors as hole superconductors

Abstract

Since their experimental discovery in 1989, the electron-doped cuprate superconductors have presented both a major challenge and a major opportunity. The major challenge has been to determine whether these materials are fundamentally different from or essentially similar to their hole-doped counterparts; a major opportunity because answering this question would strongly constrain the possible explanations for what is the essential physics that leads to high temperature superconductivity in the cuprates, which is still not agreed upon. Here we argue that experimental results over the past 30 years on electron-doped cuprate materials have provided conclusive answers to these fundamental questions, by establishing that both in hole-and electron-doped cuprates, superconductivity originates in pairing of hole carriers in the same band. We discuss a model to describe this physics that is different from the generally accepted ones, and calculate physical observables that agree with experiment, in particular tunneling characteristics. We argue that our model is simpler, more natural and more compelling than other models. Unlike other models, ours was originally proposed before rather than after many key experiments were performed. PACS numbers:

Hole superconductivity in infinite-layer nickelates

“…4, which indicates the importance of hole carriers also in this new class. Measurements of the superconducting T c and Hall coefficient at other hole concentrations will help to support our model, as will experiments reporting on the pressure dependence of T c and on tunneling asymmetry [5,7]. We don't see any reason not to expect significantly higher transition temperatures in this new class of oxide superconductors, particularly if the in-plane lattice constant can be reduced and the carrier concentration optimized.…”

“…Figure 1 shows the relevant orbitals in the NiO (or CuO) planes. The consensus for the cuprates is that both under hole or electron doping the doped carriers go into the Cu-d x 2 −y 2 O-pσ band, and give rise to superconduc- O-pσ band and induce holes into the O-pπ orbitals [7]. Instead, for hole-doped cuprates and nickelates, the doped holes go directly into the O-pπ band.…”

Jorge Eduardo Hirsch and the Hirsch-index** a Personal Chronicle

“…The answer to the first question is that he continues his research as before. In 2019 he published 5 papers in physics, [26][27][28][29][30] and as mentioned in the introduction, one in scientometrics [7].…”

Suppression of antiferromagnetic order in the electron-doped cuprate T′−La2−xCexCuO4±Tang1, Lin2, Zhang3 et al. 2021Phys. Rev. B2010View full textAdd to dashboardCite

“…due to different residing orbitals [1] or different correlation strengths caused by electron or hole charges [3,4]) or accidental (i.e. due to a band effect caused by the structure difference in the n-type cuprates [5,6]). The general formula unit of electron-doped cuprates is usually given as Ln2-xCexCuO4±d where Ln = La, Pr, Nd, Sm, Gd with gradually decreasing ionic radius.…”

“…Secondly, the phase diagram of electrondoped LCCO and hole-doped LSCO show similar characteristics, which raises a possibility for absence of electron-hole asymmetry. But how to lead to the clarification of the electron-hole symmetry/asymmetry between hole-doped and electron-doped cuprates remains a mystery [1,[3][4][5][6]13,26,27]. Thirdly, LCCO samples are grown on conducting Nb-SrTiO3 (STO) substrates and successional annealing processes are necessary for ARPES measurements, so it is difficult to obtain Tc after each procedure.…”