Interlayer magnetic-frustration–driven quantum spin disorder in the honeycomb compound In₃Cu₂VO₉

¹ Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences P. O. Box 1129, Hefei, Anhui 230031, China
² College of Physics Science and Technology, Hebei University - Baoding 071002, China
³ Department of Physics, Chinese University of Hong Kong - Shatin, New Territory, Hong Kong, China

^(a) zou@theory.issp.ac.cn

Received: 24 April 2013
Accepted: 13 August 2013

Abstract

In this paper we present the electronic and magnetic properties of the honeycomb compound In₃Cu₂VO₉. We find that the band dispersions display Dirac cone features in the nonmagnetic phase, as observed in graphene. The parent phase is a charge transfer insulator with an energy gap of about 1.5 eV. Singly occupied electrons of copper ions contribute an spin, while vanadium ions show nonmagnetism. The planar nearest-neighbor, next-nearest-neighbor and interplane superexchange couplings of Cu spins are , and , suggesting a low-dimensional antiferromagnet rather than a spin liquid. We propose that the magnetic frustration along the c-axis leads to a quantum spin disorder in In₃Cu₂VO₉, in accordance with recent experiments.