Exotic Kondo-hole band resistivity and magnetoresistance of Ce${}_{1-x}$La${}_x$Os${}_4$Sb${}_{12}$ alloys

Abstract

Electrical resistivity measurements of non-magnetic single-crystalline Ce${}_{1-x}$La${}_x$Os${}_4$Sb${}_{12}$ alloys, $x=0.02$ and 0.1, are reported for temperatures down to 20 mK and magnetic fields up to 18 T. At the lowest temperatures, the resistivity of Ce${}_{0.98}$La${}_{0.02}$Os${}_4$Sb${}_{12}$ has a Fermi-liquid-like temperature variation $\rho ={\rho }_0+A{T}^2$, but with negative $A$ in small fields. The resistivity has an unusually strong magnetic field dependence for a paramagnetic metal. The 20 mK resistivity increases by 75% between H=0 and 4 T and then decreases by 65% between 4 T and 18 T. Similarly, the $A$ coefficient increases with the field from -77 to 29$\mu \Omega$cmK${}^{-2}$ between H=0 and 7 T and then decreases to 18$\mu \Omega$cmK${}^{-2}$ for 18 T. This nontrivial temperature and field variation is attributed to the existence of a very narrow Kondo-hole band in the hybridization gap, which pins the Fermi energy. Due to disorder the Kondo-hole band has localized states close to the band edges. The resistivity for $x=0.1$ has a qualitatively similar behavior to that of $x=0.02$, but with a larger Kondo-hole band.

References in corpus (1)

• Transport properties in CeOs${}_4$Sb${}_{12}$: Possibility of the ground state being semiconducting

Cited by in corpus (2)

• Kondo holes in strongly correlated impurity arrays: RKKY driven Kondo screening and hole-hole interactions
• Pressure-induced shift of effective Ce valence, Fermi energy and phase boundaries in CeOs${}_4$Sb${}_{12}$