Segregation Energies

When determining the stability of dopants within a host, one important factor to consider is the segregation energy. This predicts the thermodynamic preference towards pinning the dopant at the surface of the host versus burying itself in the bulk.

Segregation energy values are tabulated as reported by A.V. Ruban, et. al. for multiple combinations of transition metal hosts and dopants. By definition more negative values indicate more stability towards keeping the dopant at the surface. Values where the host is the same as the dopant is the surface energy for that species.

In addition, for specifically SAAs, K. K. Rao, et. al. studied the stability of various different host and dopant combinations. The different configurations included SAA, subsurface, dimers, adatoms, and adatom + SAA. Here for most preferential configuration we attributed the following scores as per the results shown in figure 3 of the above reference:

  • SAA is the most stable: 1
  • SAA is not the most stable but is within:
    • <0.1 eV: 0.9
    • <0.2 eV: 0.8
    • <0.5 eV: 0.5
  • SAA is not the most stable by >0.5 eV: 0