Fig. 5
Proposed positive feedback effect between A(k, ω) and Σ(k, ω). (1) The onset of pairing fluctuations (gapping) in the electronic spectrum A(k, ω) will start to open a gap in the scattering spectrum Σ″ because of the removal of the low-energy electronic states. (2) Then as shown in Fig. 4 the gapping and weight transfer in Σ″ leads to strong peaks in Σ′, which give a strong mass enhancement in A(k, ω). (3) This low-energy band renormalization brings an increase in the number of low-energy k-states available to participate in the pairing (Fig. 3b, d), i.e., the effect of the pairing on A(k, ω) is enhanced by the changes in Σ(k, ω). (4) This enhancement in the pairing can feed back to the original pairing fluctuations of step 1, helping to strengthen and stabilize them. This mechanism is possible because of, or enhanced by, the huge incoherent scattering rate Σ″ present in the strange-metal incoherent normal state
