Two-stage superconductivity in the Hatsugai–Kohomoto-BCS model
Superconductivity in strongly correlated electrons can emerge out from a normal state that is beyond the Landau’s Fermi liquid paradigm, often dubbed as ‘non-Fermi liquid’. While the theory for non-Fermi liquid is still not yet conclusive, a recent study on the exactly-solvable Hatsugai–Kohomoto (HK...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2022-01-01
|
| Series: | New Journal of Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1367-2630/ac9548 |
| _version_ | 1797748401530470400 |
|---|---|
| author | Yu Li Vivek Mishra Yi Zhou Fu-Chun Zhang |
| author_facet | Yu Li Vivek Mishra Yi Zhou Fu-Chun Zhang |
| author_sort | Yu Li |
| collection | DOAJ |
| description | Superconductivity in strongly correlated electrons can emerge out from a normal state that is beyond the Landau’s Fermi liquid paradigm, often dubbed as ‘non-Fermi liquid’. While the theory for non-Fermi liquid is still not yet conclusive, a recent study on the exactly-solvable Hatsugai–Kohomoto (HK) model has suggested a non-Fermi liquid ground state whose Green’s function resembles the Yang–Rice–Zhang ansatz for cuprates (2020 Phillips et al Nat. Phys. 16 1175). Similar to the effect of on-site Coulomb repulsion in the Hubbard model, the repulsive interaction in the HK model divides the momentum space into three parts: empty, single-occupied and double-occupied regions, that are separated from each other by two distinct Fermi surfaces. In the presence of an additional Bardeen–Cooper–Schrieffer-type pairing interaction of a moderate strength, we show that the system exhibits a ‘two-stage superconductivity’ feature as temperature decreases: a first-order superconducting transition occurs at a temperature T _c that is followed by a sudden increase of the superconducting order parameter at a lower temperature ${T}_{\text{c}}^{\prime }< {T}_{\text{c}}$ . At the first stage, ${T}_{\text{c}}^{\prime }< T< {T}_{\text{c}}$ , the pairing function arises and the entropy is released only in the vicinity of the two Fermi surfaces; while at the second stage, $T< {T}_{\text{c}}^{\prime }$ , the pairing function becomes significant and the entropy is further released in deep (single-occupied) region in the Fermi sea. The phase transitions are analyzed within the Ginzburg–Landau theory. Our work sheds new light on unconventional superconductivity in strongly correlated electrons. |
| first_indexed | 2024-03-12T16:04:13Z |
| format | Article |
| id | doaj.art-08c1d5f8b1294f738c92eefcf973fd3f |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:04:13Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-08c1d5f8b1294f738c92eefcf973fd3f2023-08-09T14:25:11ZengIOP PublishingNew Journal of Physics1367-26302022-01-01241010301910.1088/1367-2630/ac9548Two-stage superconductivity in the Hatsugai–Kohomoto-BCS modelYu Li0https://orcid.org/0000-0003-0813-8517Vivek Mishra1https://orcid.org/0000-0003-2971-8764Yi Zhou2Fu-Chun Zhang3Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences , Beijing 100190, People’s Republic of ChinaKavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences , Beijing 100190, People’s Republic of ChinaBeijing National Laboratory for Condensed Matter Physics & Institute of Physics, Chinese Academy of Sciences , Beijing 100190, People’s Republic of China; Songshan Lake Materials Laboratory , Dongguan, Guangdong 523808, People’s Republic of China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100190, People’s Republic of ChinaKavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences , Beijing 100190, People’s Republic of China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences , Beijing 100190, People’s Republic of ChinaSuperconductivity in strongly correlated electrons can emerge out from a normal state that is beyond the Landau’s Fermi liquid paradigm, often dubbed as ‘non-Fermi liquid’. While the theory for non-Fermi liquid is still not yet conclusive, a recent study on the exactly-solvable Hatsugai–Kohomoto (HK) model has suggested a non-Fermi liquid ground state whose Green’s function resembles the Yang–Rice–Zhang ansatz for cuprates (2020 Phillips et al Nat. Phys. 16 1175). Similar to the effect of on-site Coulomb repulsion in the Hubbard model, the repulsive interaction in the HK model divides the momentum space into three parts: empty, single-occupied and double-occupied regions, that are separated from each other by two distinct Fermi surfaces. In the presence of an additional Bardeen–Cooper–Schrieffer-type pairing interaction of a moderate strength, we show that the system exhibits a ‘two-stage superconductivity’ feature as temperature decreases: a first-order superconducting transition occurs at a temperature T _c that is followed by a sudden increase of the superconducting order parameter at a lower temperature ${T}_{\text{c}}^{\prime }< {T}_{\text{c}}$ . At the first stage, ${T}_{\text{c}}^{\prime }< T< {T}_{\text{c}}$ , the pairing function arises and the entropy is released only in the vicinity of the two Fermi surfaces; while at the second stage, $T< {T}_{\text{c}}^{\prime }$ , the pairing function becomes significant and the entropy is further released in deep (single-occupied) region in the Fermi sea. The phase transitions are analyzed within the Ginzburg–Landau theory. Our work sheds new light on unconventional superconductivity in strongly correlated electrons.https://doi.org/10.1088/1367-2630/ac9548strongly-correlated systemunconventional superconductivitynon-Fermi liquidGinzburg–Landau theory |
| spellingShingle | Yu Li Vivek Mishra Yi Zhou Fu-Chun Zhang Two-stage superconductivity in the Hatsugai–Kohomoto-BCS model New Journal of Physics strongly-correlated system unconventional superconductivity non-Fermi liquid Ginzburg–Landau theory |
| title | Two-stage superconductivity in the Hatsugai–Kohomoto-BCS model |
| title_full | Two-stage superconductivity in the Hatsugai–Kohomoto-BCS model |
| title_fullStr | Two-stage superconductivity in the Hatsugai–Kohomoto-BCS model |
| title_full_unstemmed | Two-stage superconductivity in the Hatsugai–Kohomoto-BCS model |
| title_short | Two-stage superconductivity in the Hatsugai–Kohomoto-BCS model |
| title_sort | two stage superconductivity in the hatsugai kohomoto bcs model |
| topic | strongly-correlated system unconventional superconductivity non-Fermi liquid Ginzburg–Landau theory |
| url | https://doi.org/10.1088/1367-2630/ac9548 |
| work_keys_str_mv | AT yuli twostagesuperconductivityinthehatsugaikohomotobcsmodel AT vivekmishra twostagesuperconductivityinthehatsugaikohomotobcsmodel AT yizhou twostagesuperconductivityinthehatsugaikohomotobcsmodel AT fuchunzhang twostagesuperconductivityinthehatsugaikohomotobcsmodel |