An acceptable agreement with experiment is obtained for ε py N values ranging from -14 eV to -12 eV (the region highlighted in orange in panel e). So, we will stick to ε py N = -13 eV as a good compromise to describe both 2T-N and 2T-7N. In the following, when not otherwise stated, results will be shown for this value of ε py N . Quite interestingly, the sign of the ST gap of 2T-7N in the relevant region goes from negative values, ∆E ST = -0.22 eV at ε py N = -14