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arXiv · 2108.04118

Strong pairing in mixed dimensional bilayer antiferromagnetic Mott insulators

Annabelle Bohrdt·Lukas Homeier·Immanuel Bloch·Eugene Demler·Fabian Grusdt
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Abstract

Interacting many-body systems combining confined and extended dimensions, such as ladders and few layer systems are characterized by enhanced quantum fluctuations, which often result in interesting collective properties. Recently two-dimensional bilayer systems, such as twisted bilayer graphene or ultracold atoms, have sparked a lot of interest because they can host rich phase diagrams, including unconventional superconductivity. Here we present a theoretical proposal for realizing high temperature pairing of fermions in a class of bilayer Hubbard models. We introduce a general, highly efficient pairing mechanism for mobile dopants in antiferromagnetic Mott insulators, which leads to binding energies proportional to $t^{1/3}$, where $t$ is the hopping amplitude of the charge carriers. The pairing is caused by the energy that one charge gains when retracing a string of frustrated bonds created by another charge. Concretely, we show that this mechanism leads to the formation of highly mobile, but tightly bound pairs in the case of mixed-dimensional Fermi-Hubbard bilayer systems. This setting is closely related to the Fermi-Hubbard model believed to capture the physics of copper oxides, and can be realized by currently available ultracold atom experiments.

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Annabelle Bohrdt, Lukas Homeier, Immanuel Bloch, Eugene Demler, Fabian Grusdt. 2021-08-09. Strong pairing in mixed dimensional bilayer antiferromagnetic Mott insulators. https://doi.org/10.1038/s41567-022-01561-8

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