High-temperature superconductivity from kinetic energy

Superconductivity is usually assumed to arise from attractive interaction. In this work we show that strong pairing is possible soley from kinetic energy even without a net attraction. We demonstrate a high-temperature kinetic superconductor in a simple lattice model with nearest-neighbor hopping (t) projected onto a constrained Hilbert space, analogous to the t-J model with $J=0$, where kinetic magnetism has been previously studied. Using density matrix renormalization group (DMRG) on cylinders up to width Ly=8, we find a superconducting ground state exhibiting a key difference from high-Tc cuprates: both the pairing gap and phase stiffness increase with doping (x). We find pairing gaps, determined from spin and single-electron charge gaps, exceeding $1.5t$. This model can be realized within the double Kondo lattice model, relevant to bilayer nickelates, in the limit of strong inter-layer spin coupling (J_⊥/t → +∞) and a balancing inter-layer repulsion (V). Importantly, the double Kondo model does not fundamentally restrict J_⊥/t, suggesting the potential for high critical temperatures (Tc) approaching $0.5t$. While this idealized limit predicts large pairing gaps, we show a smooth connection to the more realistic regime with J_⊥ ~ t, albeit with a reduced pairing gap of approximately $0.1t$. Assuming t ~ 10³ K in typical solid state systems, our model suggests the exciting possibility of achieving Tc of hundreds of Kelvin. We propose searching for bilayer materials with reduced out-of-plane lattice constants to better approximate the conditions of our ideal model.