Tuning topological superconductivity within the $t$-$J$-$U$ model of twisted bilayer cuprates
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866910642814844928 |
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| author | Fidrysiak, Maciej Rzeszotarski, Bartłomiej Spałek, Józef |
| author_facet | Fidrysiak, Maciej Rzeszotarski, Bartłomiej Spałek, Józef |
| contents | We carry out a theoretical study of unconventional superconductivity in twisted bilayer cuprates (TBC) as a function of electron density and layer twist angle. The bilayer $t$-$J$-$U$ model is employed and analyzed within the framework of a generalized variational wave function approach in the statistically-consistent Gutzwiller formulation. The constructed phase diagram encompasses both gapless $d$-wave state (reflecting the pairing symmetry of untwisted copper-oxides) and gapped $d+\mathrm{e}^{iφ}d$ phase that breaks spontaneously time-reversal-symmetry (TRS) and is characterized by nontrivial Chern number. We find that $d+\mathrm{e}^{iφ}d$ state occupies a non-convex butterfly-shaped region in the doping vs. twist-angle plane, and demonstrate the presence of previously unreported reentrant TRS-breaking phase on the underdoped side of the phase diagram. This circumstance supports the emergence of topological superconductivity for fine-tuned twist angles in TBC away from $45^\circ$. Our analysis of the microscopically derived Landau free energy functional points toward sensitivity of the superconducting order parameter to small perturbations close to the topological state boundary. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_04379 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Tuning topological superconductivity within the $t$-$J$-$U$ model of twisted bilayer cuprates Fidrysiak, Maciej Rzeszotarski, Bartłomiej Spałek, Józef Superconductivity Strongly Correlated Electrons We carry out a theoretical study of unconventional superconductivity in twisted bilayer cuprates (TBC) as a function of electron density and layer twist angle. The bilayer $t$-$J$-$U$ model is employed and analyzed within the framework of a generalized variational wave function approach in the statistically-consistent Gutzwiller formulation. The constructed phase diagram encompasses both gapless $d$-wave state (reflecting the pairing symmetry of untwisted copper-oxides) and gapped $d+\mathrm{e}^{iφ}d$ phase that breaks spontaneously time-reversal-symmetry (TRS) and is characterized by nontrivial Chern number. We find that $d+\mathrm{e}^{iφ}d$ state occupies a non-convex butterfly-shaped region in the doping vs. twist-angle plane, and demonstrate the presence of previously unreported reentrant TRS-breaking phase on the underdoped side of the phase diagram. This circumstance supports the emergence of topological superconductivity for fine-tuned twist angles in TBC away from $45^\circ$. Our analysis of the microscopically derived Landau free energy functional points toward sensitivity of the superconducting order parameter to small perturbations close to the topological state boundary. |
| title | Tuning topological superconductivity within the $t$-$J$-$U$ model of twisted bilayer cuprates |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2310.04379 |