1. Doping dependence of superconductivity on a honeycomb lattice within the framework of kinetic-energy-driven superconductivity.
- Author
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Lan, Yu, Yu, Xian-Feng, and Zhang, Li-Ting
- Subjects
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CUPRATES , *SUPERCONDUCTIVITY , *HIGH temperature superconductors , *HONEYCOMB structures , *EXCHANGE interactions (Magnetism) , *COUPLING constants - Abstract
Unconventional superconductivity on a honeycomb lattice has received increasing interest since the discovery of graphene primarily due to the similarities between materials with a honeycomb lattice and cuprate superconductors. Many theoretical studies have been conducted on superconductivity on a honeycomb lattice, however, a consistent picture is still lacking. In this paper, we have extended the theory of kinetic-energy-driven superconductivity, which has been developed to investigate unconventional superconductivity in cuprate superconductors, to explore superconductivity on a honeycomb lattice within the t-J model. Our results demonstrate that the charge-carrier pair gap parameter with d x 2 − y 2 + i d x y -wave symmetry exhibits a dome-like shape as a function of doping, with superconductivity emerging at a certain doping concentration and disappearing at high doping levels, similar to what has been observed in cuprate and cobaltate superconductors. Furthermore, the charge-carrier pair gap parameter decreases with increasing the value of J ∕ t (the ratio between the antiferromagnetic exchange coupling constant and the nearest-neighbor hopping integral), and approaches zero when J ∕ t reaches a sufficiently large value. This indicates that the antiferromagnetic order will suppress the superconducting state and a sufficiently strong exchange coupling will completely destroy the superconductivity. Taking into account our present results together with the corresponding results of cuprate and cobaltate superconductors, it appears that the dome-like shape of the doping dependence of the charge-carrier pair gap parameter may be a common feature in doped Mott insulators. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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