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arXiv · 2308.03401

Can dd excitations mediate pairing ?

Francesco Barantani·Christophe Berthod·Dirk van der Marel
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Abstract

The Cu-$3d$ states in the high-$T_c$ cuprates are often described as a single band of $3d_{x^2-y^2}$ states, with the other four $3d$ states having about 2 to 3 eV higher energy due to the lower-than-octahedral crystal field at the copper sites. However, excitations to these higher energy states observed with RIXS show indications of strong coupling to doped holes in the $3d_{x^2-y^2}$ band. This relaunches a decades-old question of the possible role of the orbital degrees of freedom that once motivated Bednorz and M\"uller to search for superconductivity in these systems. Here we explore a direction different from the Jahn-Teller electron-phonon coupling considered by Bednorz and M\"uller, namely the interaction between holes mediated by $dd$ excitations.

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Francesco Barantani, Christophe Berthod, Dirk van der Marel. 2023-08-07. Can dd excitations mediate pairing ?. https://doi.org/10.1016/j.physc.2023.1354321

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