Unusual superexchange pathways in a Ni triangular lattice of NiGa${}_2$S${}_4$ with negative charge-transfer energy

K. Takubo, T. Mizokawa, J. -Y. Son +5

We have studied the electronic structure of the Ni triangular lattice in NiGa${}_2$S${}_4$ using photoemission spectroscopy and subsequent model calculations. The cluster-model analysi…