Fig. 2: Microwave enhancement of superconducting gap in 1D SSH model.
From: Quantum geometry induced microwave enhancement of superconducting order in flat bands
a 1D bipartite lattice with nearest neighbor intra- and inter-cell hoppings denoted by t+ and t− respectively. Here, we show the band structure for λ = 0.1 (blue) and 0.8 (red). (b, c) Distribution of intra- and interband velocity matrix elements, \({v}_{k}^{+\pm }\), for values of λ corresponding to dispersion in (a). Reduced bandwidth implies suppressed \({v}_{k}^{++}\). On the other hand, for narrow bands large \({v}_{k}^{+-}\) is distributed throughout the k-space. d Quantum geometry governed superconducting gap enhancement (green) in comparison with the conventional contribution (magneta). Evidently, δΔ/Δ0 due to quantum geometry peaks for narrow bands with sufficient phase space for scattering. It decreases when bandwidth increases (for larger λ), and is suppressed in extremely flat bands (smaller λ) due to vanishing \({f}_{\alpha {\bf{k}}}^{0}-{f}_{\alpha {{\bf{k}}}^{{\prime} }}^{0}\). The conventional contribution increases with increase in λ due to increasing v++. Here we use μ = u, Δ = 0.1u, ω = 0.05u, T/Tc = 0.05 and set \({V}_{0}^{2}{N}_{{\rm{imp}}}{e}^{2}| {\mathcal{E}}{| }^{2}/(\hslash {\tau }^{-1})=0.03{u}^{3}{a}^{-2}\).
