  The recently demonstrated unconventional superconductivity in twisted bilayer
graphene (tBLG) opens the possibility for interesting applications of
two-dimensional layers that involve correlated electron states. Here we explore
the possibility of modifying electronic correlations by the application of
uniaxial pressure on the weakly interacting layers, which results in increased
interlayer coupling and a modification of the magic angle value and associated
density of states. Our findings are based on first-principles calculations that
accurately describe the height-dependent interlayer coupling through the
combined use of Density Functional Theory and Maximally localized Wannier
functions. We obtain the relationship between twist angle and external pressure
for the magic angle flat bands of tBLG. This may provide a convenient method to
tune electron correlations by controlling the length scale of the superlattice.
