Localization effects of kondo semimetals CeNiSn and CeRhSb

Ce3Cu3Sb4: a Canted Antiferromagnetic Semimetal

“…So-called Kondo insulators like Ce 3 Pt3 Bi4 [5] or CeNiSn [6] are materials which seem to have a gap and the Fermi level in the gap, so they behave like semiconductors. Whereas this has been verified by far infrared optical measurements in the case of Ce3Pt3Bi4 [7] (a material in which Ce is formally (43) tetravalent) it has been shown recently that in carefully prepared CeNiSn single crystals the features of a gap disappear [8]. Even in the high ΤC superconductor Nd2-xCexCuO4 Ce again plays an anomalous role, inasmuch as this is the first n-type high ΤC superconductor [9].…”

Cerium intermetallics with TiNiSi-type structure

“…This result along with the large γ = 42 mJ mol −1 K −2 supports the presence of a residual density of states at the Fermi level. Therefore the ground state of CeNiSn is not a Kondo semiconducting state, but more a semimetallic state with a pseudogap which closes along the a axis [80,206]. Evidence for a quasiparticle gap in CeNiSn was generated by tunneling spectroscopy, the most direct probe to investigate the gap.…”

ESR experiments on the Kondo insulator CeNiSn

“…With decreasing temperature the electric resistance ρ shows a drastic increase below 7K. This can be explained by the opening of an energy gap in the electronic density of states [2,3]. As described in these papers, a serious problem of resistance measurements was the strong dependence of the results on the sample quality, especially on the concentrations of impurities in the required single crystals, and it seemed, that the purest single crystals reveal metallic behavior down to the lowest temperatures.…”