2009/12/31 by Gia-Wei Chern, Natalia B. Perkins, Natalia Perkins +1 · 2 citations
Chemistry · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Atomic physics #Chemistry #Condensed matter physics #Crystallography #Degenerate energy levels #Ground state #Magnetic and transport properties of perovskites and related materials #Physics #Physics of Superconductivity and Magnetism #Pyrochlore #Quantum mechanics #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.81.125127
published as Phys. Rev. B 81, 125127 (2010) · 10 pages, 9 figures, references added
arxiv created 2010/01/03 · openalex publication_date 2010/03/26 · arxiv updated 2010/07/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present an analytical model of orbital ordering in vanadium spinel MnV2O4. The model is based on recent first-principles calculation indicating a strong trigonal distortion at the vanadium sites of this compound [S. Sarkar, T. Maitra, R. Valent'\i, and T. Saha-Dasgupta Phys. Rev. Lett. 102, 216405 (2009)]. At the single-ion level, the trigonal crystal field leaves a doubly degenerate atomic ground state and breaks the approximate rotational symmetry of t2g orbitals. We find that the effective interaction between the low-energy doublets is described by a quantum antiferromagnetic 120\ifmmode^∘\else\textdegree\fi model on the pyrochlore lattice. We obtain the classical ground state and show its stability against quantum fluctuations. The corresponding orbital order consisting of two inequivalent orbital chains is consistent with the experimentally observed tetragonal symmetry. A periodic modulation of electron density function along orbital chains is shown to arise from the staggering of local trigonal axes. In the presence of orbital order, single-ion spin anisotropy arising from relativistic spin-orbit interaction stabilizes the experimentally observed orthogonal magnetic structure.