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TT: Fachverband Tiefe Temperaturen

TT 12: Correlated Electrons: Frustrated Magnets - General 1

TT 12.6: Vortrag

Montag, 20. März 2017, 16:15–16:30, HSZ 03

Spin Frustration in an Organic Radical Ion Salt Based on a Kagome-Coupled Chain Structure — •Lars Postulka¹, Stephen M. Winter¹, Bernd Wolf¹, Adam G. Mihailov², Aaron Mailman², Adbeljalil Assoud², Craig M. Robertson³, Richard T. Oakley², and Michael Lang¹ — ¹Physikalisches Institut, Goethe Universität, SFB/TR49, Frankfurt, DE — ²Dep. of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada — ³Dep. of Chemistry, University of Liverpool, Liverpool L69 7ZD, United Kingdom

Frustrated quantum spin systems have attracted enormous interest in experimental and theoretical studies as these systems are expected to host spin liquid states. A model system for such frustrated quantum magnets is the kagome lattice with S=1/2 moments at the lattice vertices. Here we present a purely organic variant built out of quinoidal bisdithiazole [BT]⁺ radicals and [GaBr₄]⁻.The packing pattern of the radical cations provides a rare example of an organic kagome basket structure. Magnetic measurements over a wide temperature range 30 mK < T < 300 K suggest strongly frustrated AFM interactions of the scale of J/k_B ≈ 30 K, but reveal no anomalies that would be associated with magnetic order. The high-temperature part of the susceptibility can be described in a coupled-chain model. By combining results from high-temperature series expansion and density functional theory we could resolve that these chains are coupled in a distorted kagome lattice[1].

[1] L. Postulka et al., J. Am. Chem. Soc. 138, 10738 (2016)