Structures and Physical Properties of CsV$_2$Se$_{2-x}$O and V$_2$Se$_2$O

Hai Lin; Jin Si; Xiyu Zhu; Kehan Cai; Hao Li; Lu Kong; Xiaodong Yu; Hai-Hu Wen

doi:10.1103/PhysRevB.98.075132

paper

Structures and Physical Properties of CsV $_{2}$ Se $_{2 - x}$ O and V $_{2}$ Se $_{2}$ O

arXiv:1803.00703 · doi:10.1103/PhysRevB.98.075132

Abstract

By using solid-state reactions, we successfully synthesize new oxyselenides CsV $_{2}$ Se $_{2 - x}$ O (x = 0, 0.5). These compounds containing V $_{2}$ O planar layers with a square lattice crystallize in the CeCr $_{2}$ Si $_{2}$ C structure with the space group of $P 4/ mmm$ . Another new compound V $_{2}$ Se $_{2}$ O which crystallizes in space group $I 4/ mmm$ is fabricated by topochemical deintercalation of cesium from CsV $_{2}$ Se $_{2}$ O powder with iodine in tetrahydrofuran(THF). Resistivity measurements show a semiconducting behavior for CsV $_{2}$ Se $_{2}$ O, while a metallic behavior for CsV $_{2}$ Se $_{1.5}$ O, and an insulating feature for V $_{2}$ Se $_{2}$ O. A charge- or spin-density wave-like anomaly has been observed at 168 K for CsV $_{2}$ Se $_{2}$ O and 150 K for CsV $_{2}$ Se $_{1.5}$ O, respectively. And these anomalies are also confirmed by the magnetic susceptibility measurements. The resistivity in V $_{2}$ Se $_{2}$ O exhibits an anomalous log(1/ $T$ ) temperature dependence, which is similar to the case in parent phase or very underdoped cuprates indicating the involvement of strong correlation. Magnetic susceptibility measurements show that the magnetic moment per V-site in V $_{2}$ Se $_{2}$ O is much larger than that of CsV $_{2}$ Se $_{2 - x}$ O, which again suggests the correlation induced localization effect in the former.

5 pages, 4 figures

Structures and Physical Properties of CsV2​Se2−x​O and V2​Se2​O

Abstract

Structures and Physical Properties of CsV $_{2}$ Se $_{2 - x}$ O and V $_{2}$ Se $_{2}$ O