Work functions of metal hexaborides: Density functional study

We present a systematic theoretical investigation on the work functions of five closed surfaces of metal hexaborides including LaB6, BaB6, CaB6, CeB6, SrB6 and SmB6. The results are in a close agreement with available experimental measurements and previous theoretical findings. The variations of the work function display a good trend. For BaB6, CaB6 and SrB6, the increasing order is ϕ(100) < ϕ(110) < ϕ(211) < ϕ(112) < ϕ(111). For CeB6, LaB6, and SmB6, the sequence is somewhat different: ϕ(100) < ϕ(211) < ϕ(112) < ϕ(110) < ϕ(111). The work function changes with the metal hexaborides series have also been discussed. The increasing order of the (100) surface is LaB6(100) < CeB6(100) < SmB6(100) < SrB6(100) < BaB6(100) < CaB6(100). The orders for the (110) and (111) surface are similar: BaB6(110, 111) < SrB6(110, 111) < LaB6(110, 111) < CeB6(110, 111) < CaB6(110, 111) < SmB6(110, 111). For the (112) and (211) surface, the sequence is BaB6(112, 211) < LaB6(112, 211) < CeB6(112, 211) < SrB6(112, 211) < SmB6(112...