Pressure induced magnetism in rotated graphene bilayers

Abstract

Using ab initio methods based on the density functional theory we show that rotated graphene bilayers at angles different from the magic ones can have an electronic spectrum similar to those by applying moderate external pressures. We find that for an angle of $5.08^{\circ}$ and a pressure of 2.19 GPa the spin restricted spectrum displays a flat band at the Fermi level similar to the one found at magic angles. In addition, the spin unrestricted calculations show a correlated ferromagnetic ground state with a total magnetic moment of 3.7 $\mu_{B}$ per unit cell being mostly localized in the AA stacking region of the Moir\'{e} pattern. The possibility of antiferromagnetic order is considered but not calculated. Doping the system destroys the magnetic moments. The plausibility of BCS superconductivity in the doped system is analyzed.