Observation of Metal–Insulator Transition in Hollandite Vanadate, K₂V₈O₁₆

Theoretical study of the electronic states of hollandite vanadateK2V8O16

“…This situation seems to suggest that the formation of nonmagnetic local spin-singlets occurs below the transition temperature but that there still remain interacting magnetic spins. 3 The broad nonmagnetic spectrum in the insulating region observed in a recent NMR experiment 14 might also be interesting in this respect.…”

“…Recently, Isobe et al 3 reported that, in hollandite vanadate K 2 V 8 O 16 , a metal-insulator transition (MIT) occurs at ∼ 170 K, which is accompanied by the rapid reduction of the magnetic susceptibility. Below the transition temperature, a characteristic superlattice of √ 2a × √ 2a × 2c is observed, 3 whereby a possible CO phase transition accompanied by the spin-singlet formation was proposed.…”

Synthesis and structural, magnetic, thermal, and transport properties of several transition metal oxides and aresnides

“…[122] The presence of a quantum phase transition from a weakly localized state to a metallic state in BaRu 6 O 12 has been reported. [123] The magnetic susceptibilties of α-YV …”

Colossal Magnetoresistance and Magnetism of NaCr2O4

“…Because the structure is composed of double rutile chains as shown in Fig. 1, the compound is expected to show interesting electronic properties originating from spin frustrations and one-dimensional electron correlations, as in the case of other compounds with double rutile chain structures [2][3][4][5][6][7][8]. In addition to the structural feature, the compound has mixed-valence state of Cr 3.5+ although less Cr oxides accept a mixed-valence state.…”

“…A trivalent Cr ion octahedrally coordinated by oxygens has three t 2g electrons to become very stable due to the half-filled t 2g orbitals. Thus, a tetravalent Cr ion tends to make a hole on the ligand oxygen to keep the half-filled t 2g orbitals; the electronic configuration is represented as 3d 3 L, where L denotes a ligand hole. The ligand holes often cause interesting properties.…”