Structural and magnetic properties of “one-dimensional” barium vanadium triselenide

Exotic magnetic properties in Zintl phase BaVSe3: a theoretically supported experimental investigation

The magnetic properties of Zintl phase barium vanadium selenide (BaVSe3) were investigated experimentally and theoretically.

Ba9V3Se15: a novel compound with spin chains

In this work, a novel compound Ba₉V₃Se₁₅ with one-dimensional (1D) spin chains was synthesized under high-pressure and high-temperature conditions. It was systematically characterized via structural, magnetic, thermodynamic and transport measurements. Ba₉V₃Se₁₅ crystallizes into a hexagonal structure with a space group of P-6c2 (188) and the lattice constants of a  =  b  =  9.5745(7) Å and c  =  18.7814(4) Å. The crystal structure consists of face-sharing octahedral VSe₆ chains along c axis, which are trimeric and arranged in a triangular lattice in ab-plane. Ba₉V₃Se₁₅ is a semiconductor and undergoes complex magnetic transitions. In the zero-field-cooled (ZFC) process with magnetic field of 10 Oe, Ba₉V₃Se₁₅ sequentially undergoes ferrimagnetic and spin cluster glass transition at 2.5 K and 3.3 K, respectively. When the magnetic field exceeds 50 Oe, only the ferrimagnetic transition can be observed. Above the transition temperature, the specific heat contains a significant magnetic contribution that is proportional to T ^1/2. The calculation suggests that the nearest neighbor (NN) intra-chain antiferromagnetic exchange J ₁ is much larger than the next nearest neighbor (NNN) intra-chain ferromagnetic exchange J ₂. Therefore, Ba₉V₃Se₁₅ can be regarded as an effective ferromagnetic chains with effective spin-1/2 by the formation of the V(2)^(↓) V(1)^(↑) V(2)^(↓) cluster.

Electronic correlations in vanadium chalcogenides: BaV Se(3) versus BaV S(3)

Albeit structurally and electronically very similar, at low temperature the quasi-one-dimensional vanadium sulfide BaV S(3) shows a metal-to-insulator transition via the appearance of a charge-density-wave state, while BaV Se(3) apparently remains metallic down to zero temperature. This different behavior upon cooling is studied by means of density functional theory and its combination with the dynamical mean-field theory and the rotationally invariant slave-boson method. We reveal several subtle differences between these chalcogenides that provide indications for the deviant behavior of BaV Se(3) at low temperature. In this regard, a smaller Hubbard U in line with an increased relevance of the Hund's exchange J plays a vital role.