Electronic structures of CeNiSn, CePdSn, and CePtSn

We have performed self-consistent first-principles band-structure calculations on the isostructural heavy fermion materials CeNiSn, CePdSn, and CePtSn. CeNiSn behaves as a heavy-fermion compound down to 7 K where a small, anisotropic energy gap develops. In contrast CePdSn and CePtSn have magnetic, metallic ground states, both with ${\mathit{T}}_{\mathit{N}}$=7.5 K. Our calculations reveal band structures in good agreement with experimental observations. We find an insulating band structure for CeNiSn which displays no tendency to form a magnetic ground state. We interpret this to mean that the energy gap may be due to hybridization. For CePdSn and CePtSn we find metallic ground states and spin-polarized calculations reveal the existence of a stable magnetic state for CePdSn with a moment of 0.86${\mathrm{\mu }}_{\mathit{B}}$ per cerium atom, while for CePtSn a magnetic state is only obtained when the lattice is expanded.