Au-N clusters (N=1-6) supported on MgO(100) surfaces: Effect of exact exchange and dispersion interactions on adhesion energies

作者：Paz Borbon Lauro Oliver^*; Barcaro Giovanni; Fortunelli Alessandro; Levchenko Sergey V

来源：Physical Review B, 2012, 85(15): 155409.

DOI：10.1103/PhysRevB.85.155409

The energetics of an Au adatom and Au-N clusters (N = 2-6) supported on pristine and reduced MgO(100) surfaces is analyzed using an all-electron full-potential density functional theory approach. A hierarchy of exchange-correlation functional approximations is employed, ranging from the generalized gradient approximation [Perdew-Burke-Ernzerhof (PBE), revised PBE (RPBE)] to hybrid functionals [PBE0, Heyd-Scuseria-Ernzerhof (HSE06)] to exact exchange plus correlation in the random phase approximation (EX-cRPA/cRPA+). The analysis of different terms in the electronic Hamiltonian, contributing to calculated adhesion energies (E-adh) for the Au adatom, shows that reducing the self-interaction error leads to smaller E-adh values. On the contrary, the energy barriers for diffusion of an Au adatom at the pristine surface significantly increase. For Au-N clusters (N > 1), dispersion effects, not accounted for by the generalized gradient approximation or hybrid functionals, start to make an increasingly important contribution to the adhesion energy.

• 出版日期2012-4-4