The number of citrates in the system was set to neutralize the total charge of TMA-Au NPs. To create the conventional superlattice unit cell, we built on the simulations from our previous work. In particular, we determined the distance at which the NPs self-assembled by measuring the spacing between the two NPs' centers of mass (see Figure ). Since we know that the NPs self-assemble into an FCC lattice (from the small-angle X-ray scattering bar via the Berendsen barostat method with τ p = 10 ps and temperature coupling time of τ T = 2 ps. Finally, we employed the same NPT scheme to perform 20 µs long production runs, at T = 300 K or T = 333 K and p = 2 × 10 -6 bar. We used a 20-fs integration time-step, standard in Martini models. In the CG-MD simulations with the external field, a constant, uniform electrostatic field along the x -direction was applied, with different values of the amplitude E, ranging from 0.005 V nm -1 to 0.11 V nm -1 .