NiS - An unusual self-doped, nearly compensated antiferromagnetic metal,
S. K. Panda, I. Dasgupta, E. Şaş10ğlu, S. Blügel and D. D. Sarma a&scidel;ioglu, S. Blugel, and D. D. Sarma,
Scientific Reports 3, 2995 (2013).
NiS, exhibiting a text-book
example of a first-order transition with many unusual properties at low temperatures, has been variously described
in terms of conflicting descriptions of its ground state during the past several decades. We calculate these physical
properties within first-principle approaches based on the density functional theory and conclusively establish that
all experimental data can be understood in terms of a rather unusual ground state of NiS that is best described as a
self-doped, nearly compensated, antiferromagnetic metal, resolving the age-old controversy. We trace the origin of
this novel ground state to the specific details of the crystal structure, band dispersions and a sizable Coulomb
interaction strength that is still sub-critical to drive the system in to an insulating state. We also show how the
specific antiferromagnetic structure is a consequence of the less-discussed 90° and less than 90° superexchange
interactions built in to such crystal structures.
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