Structural and electronic properties of the Nb$_4$-cluster compound Ga$_{1.33}$Nb$_4$X$_8$ (X = S, Se)
| dc.creator | Niazi, Asad | |
| dc.creator | Rastogi, A. K. | |
| dc.date | 2001-10-08 | |
| dc.date.accessioned | 2026-07-07T02:42:57Z | |
| dc.date.available | 2026-07-07T02:42:57Z | |
| dc.description | We report resistivity, thermopower and magnetic susceptibility measurements on the Nb$_4$-cluster compounds Ga$_{1.33}$Nb$_4$X$_{8}$ (X = S, Se), derived from vacancy ordered spinels A$_x$T$_4$X$_8$. The cubic selenide phase is insulating and its resistivity crosses over from $\lnρ \sim T^{-1}$ to $\sim T^{-1/2}$ on cooling below 150 K, indicating variable range hopping (VRH) conduction at low temperatures. This is similar to that previously reported for V$_4$ and Mo$_4$ cluster compounds. The rhombohedrally distorted sulfide is metallic and shows a minimum in resistance at $\sim $ 56 K below which the resistivity varies as $ρ(T) \sim T^{-1/2}$. The thermopower of the selenide becomes temperature independent below the crossover temperature. These Nb$_4$ compounds exhibit enhanced Pauli-paramagnetic magnetic susceptibility ($χ$) irrespective of their transport properties and both undergo a similar transition in $χ(T) \sim 30$ K. We discuss these properties in the model of hopping conduction under long-range Coulomb repulsion effects and derive consistency between some of the transport and magnetic parameters. | |
| dc.description | 8 two-column pages including 6 .eps figures, latex2.09, revetx3.1 | |
| dc.identifier | https://arxiv.org/abs/cond-mat/0110155 | |
| dc.identifier | http://arxiv.org/abs/cond-mat/0110155 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/18355 | |
| dc.subject | Strongly Correlated Electrons | |
| dc.subject | Materials Science | |
| dc.title | Structural and electronic properties of the Nb$_4$-cluster compound Ga$_{1.33}$Nb$_4$X$_8$ (X = S, Se) | |
| dc.type | text |