Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 12: Correlated Electrons: Frustrated Magnets - General 1

TT 12.2: Vortrag

Montag, 20. März 2017, 15:15–15:30, HSZ 03

Anisotropic kagome lattice as the origin of canted antiferromagnetism in barlowite — •Alexander A. Tsirlin¹, Ronald Zinke², Ioannis Rousochatzakis³, Helge Rosner⁴, and Johannes Richter² — ¹EP VI, EKM, University of Augsburg, Germany — ²Institute of Theoretical Physics, University of Magdeburg, Germany — ³School of Physics, University of Minnesota, Minneapolis, US — ⁴MPI for Chemical Physics of Solids, Dresden, Germany

Barlowite is a recent addition to the family of spin-1/2 kagome minerals that, despite its reported three-fold symmetry of the crystal structure, reveals long-range magnetic order below 15 K with a weak remnant magnetization. Using density-functional band-structure calculations along with the effective theory and coupled-cluster method for spin Hamiltonians, we propose that the disordered arrangement of the interlayer Cu site gives rise to a tangible deformation of the kagome layers. Their local configurations can be represented by a combination of weakly coupled linear trimers and spatially anisotropic kagome lattice. While the former give rise to simple antiferromagnetic order, the latter supports canted antiferromagnetic order driven by quantum fluctuations and reinforced by Dzyaloshinsky-Moriya anisotropy. This mechanism stabilizes canted antiferromagnetic order with a relatively low net moment lying in the kagome plane, which is only possible when geometrical distortion of the kagome lattice is taken into account.