Details

Autor(en) / Beteiligte

• Vasiliev, A. N.
• Volkova, O. S.
• Zvereva, E. A.
• Koshelev, A. V.
• Urusov, V. S.
• Chareev, D. A.
• Petkov, V. I.
• Sukhanov, M. V.
• Rahaman, B.
• Saha-Dasgupta, T.

Titel

Valence-bond solid as the quantum ground state in honeycomb layered urusovite CuAl ( As O 4 ) O

Ist Teil von

• Physical review. B, Condensed matter and materials physics, 2015-04, Vol.91 (14), Article 144406

Erscheinungsjahr

2015

Link zum Volltext

Quelle

APS_美国物理学会过刊

Beschreibungen/Notizen

• The synthetic mineral urusovite CuAl (AsO sub(4))O was prepared through the wet chemistry route and characterized over a wide temperature range in terms of studies of magnetization, specific heat, and X-band electron spin resonance. The basic structural units of the compound are distorted square pyramids CuO sub(5) assembled into corrugated honeycomb layers separated by AsO sub(4) and AlO sub(4) tetrahedrons. Both thermodynamic and resonant measurements indicate that CuAl (AsO sub(4))O is a spin gap system with a gap of ~ 350 K. The electronic structure calculations performed within the framework of density functional theory suggest a weakly interacting dimer model with antiferromagnetic signs for both intradimer and interdimer superexchange interactions. This establishes the valence bond solid as the quantum ground state of the title compound. The pronounced discrepancy between experimental data and calculations within the weakly interacting dimer model at elevated temperatures is ascribed in part to the steep increase of the intradimer exchange interaction parameter driven by the thermal expansion effects.