Mott correlations in ABC graphene trilayer aligned with hBN

CALDERÓN, M. J.; CAMJAYI, A.; BASCONES, E.

Physical Review B

American Physical Society

Año: 2022 vol. 106

2469-9950

ABC trilayer graphene aligned with hexagonal boron nitride (ABC/hBN) and other moiré systems have showninsulating phases at integer fillings of the moiré lattice. The role of Mott physics in these insulating states hasbeen questioned by observations of correlated states in a nonaligned ABC trilayer, but recent photocurrentexperiments in aligned samples are consistent with the existence of a Mott insulating state at half filling.Using dynamical mean-field theory we address the effect of Mott correlations in ABC/hBN. We show that,at experimentally relevant interaction values, the electronic states are strongly affected by a significant spectralweight transfer not present without alignment to hBN. This effect, which emerges at interactions considerablysmaller than U Mott (at which the Mott metal-insulator transition takes place) and does not require symmetry break-ing, also impacts the electronic properties at temperatures above the ordering transitions producing anomaloustemperature and doping dependencies. Close to the Mott transition, the intramoiré unit cell interactions promotean antiferromagnetic state, probably breaking the C 3 symmetry, that would compete with the ferromagneticexchange interactions to determine the ground state.