Topological disorder triggered by interaction-induced flattening of electron spectra in solids

We address the intervention of classical-like behavior, well documented in experimental studies of strongly correlated electron systems of solids that emerges at temperatures $T$ far below the Debye temperature $T_D$. We attribute this unexpected phenomenon to spontaneous rearrangement of the conventional Landau state beyond a critical point at which the topological stability of this state breaks down, leading to the formation of an interaction-induced flat band adjacent to the nominal Fermi surface. We demonstrate that beyond the critical point, the quasiparticle picture of such correlated Fermi systems still holds, since the damping of single-particle excitations remains small compared with the Fermi energy $T_F=p_F^2\mathrm{/}2m_e$. A Pitaevskii-style equation for determination of the rearranged quasiparticle momentum distribution $n_*({\bf p})$isderived,whichappliestoexplanationofthelinear-in-$T$ behavior of the resistivity $\rho (T)$ found experimentally.