2016/09/02 by Makiko Okada, Hidekazu Tanaka, Nobuyuki Kurita +10 · 16 citations
Chemistry · Physics and Astronomy · #Advanced Condensed Matter Physics #Chemistry #Condensed matter physics #Density functional theory #Frustration #Magnetic field #Magnetization #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Spin (aerodynamics) #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.94.094421
published in Physical review. B./Physical review. B 94(9) (American Physical Society) · 9 pages, 7 figures, to appear in Phys. Rev. B
arxiv created 2016/09/02 · openalex created_date 2016/09/16 · openalex publication_date 2016/09/20 · arxiv updated 2016/10/19 · openalex updated_date 2026/08/06
We synthesized single crystals of composition Ba2CuSi2O6Cl2 and investigated their quantum magnetic properties. The crystal structure is closely related to that of the quasi-two-dimensional (2D) dimerized magnet BaCuSi2O6 also known as Han purple. Ba2CuSi2O6Cl2 has a singlet ground state with an excitation gap of \mathrm\ensuremathΔ/kB=20.8 K. The magnetization curves for two different field directions almost perfectly coincide when normalized by the g factor except for a small jump anomaly for a magnetic field perpendicular to the c axis. The magnetization curve with a nonlinear slope above the critical field is in excellent agreement with exact-diagonalization calculations based on a 2D coupled spin-dimer model. Individual exchange constants are also evaluated using density functional theory (DFT). The DFT results demonstrate a 2D exchange network and weak frustration between interdimer exchange interactions, supported by weak spin-lattice coupling implied from our magnetostriction data. The magnetic-field-induced spin ordering in Ba2CuSi2O6Cl2 is described as the quasi-2D Bose-Einstein condensation of triplets.