Abstract

Twisted bilayer graphene provides a paradigmatic platform for exploring the interplay between electronic topology and strong correlations. Within the topological heavy fermion model, topology and electron interactions are brought together by including a weak hybridization between the bands of itinerant c- and localized f-electrons. This work develops an analytic theory of the quasiparticle dispersion and lifetime in the Mott semimetal, reformulating the interacting flat-band Hamiltonian as an on-site Hubbard interaction on a set of non-orthogonal orbitals and computing the electron Green's function using the equation-of-motion method. The authors show the emergence of well-defined low-energy quasiparticles with dispersion and relaxation rate proportional to the interaction strength, and obtain the spectral function across the Brillouin zone.

Abstract

Twisted bilayer graphene provides a paradigmatic platform for exploring the interplay between electronic topology and strong correlations. Within the topological heavy fermion model, topology and electron interactions are brought together by including a weak hybridization between the bands of itinerant c- and localized f-electrons. This work develops an analytic theory of the quasiparticle dispersion and lifetime in the Mott semimetal, reformulating the interacting flat-band Hamiltonian as an on-site Hubbard interaction on a set of non-orthogonal orbitals and computing the electron Green's function using the equation-of-motion method. The authors show the emergence of well-defined low-energy quasiparticles with dispersion and relaxation rate proportional to the interaction strength, and obtain the spectral function across the Brillouin zone.

Abstract

Twisted bilayer graphene provides a paradigmatic platform for exploring the interplay between electronic topology and strong correlations. Within the topological heavy fermion model, topology and electron interactions are brought together by including a weak hybridization between the bands of itinerant c- and localized f-electrons. This work develops an analytic theory of the quasiparticle dispersion and lifetime in the Mott semimetal, reformulating the interacting flat-band Hamiltonian as an on-site Hubbard interaction on a set of non-orthogonal orbitals and computing the electron Green's function using the equation-of-motion method. The authors show the emergence of well-defined low-energy quasiparticles with dispersion and relaxation rate proportional to the interaction strength, and obtain the spectral function across the Brillouin zone.

Abstract

Twisted bilayer graphene provides a paradigmatic platform for exploring the interplay between electronic topology and strong correlations. Within the topological heavy fermion model, topology and electron interactions are brought together by including a weak hybridization between the bands of itinerant c- and localized f-electrons. This work develops an analytic theory of the quasiparticle dispersion and lifetime in the Mott semimetal, reformulating the interacting flat-band Hamiltonian as an on-site Hubbard interaction on a set of non-orthogonal orbitals and computing the electron Green's function using the equation-of-motion method. The authors show the emergence of well-defined low-energy quasiparticles with dispersion and relaxation rate proportional to the interaction strength, and obtain the spectral function across the Brillouin zone.