Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 58: Transport: Poster Session

TT 58.32: Poster

Mittwoch, 9. März 2016, 15:00–18:30, Poster D

Charge Carrier Dynamics in κ-(BEDT-TTF)₂Cu[N(CN)₂]Cl: From Mott Insulator to Quantum Spin Liquid — •Jana-Isabelle Polzin¹, Benedikt Hartmann¹, Takahiko Sasaki², and Jens Müller¹ — ¹Institute of Physics, Goethe University Frankfurt, Germany — ²Institute for Materials Research, Tohoku University, Sendai, Japan

The organic charge transfer salts κ-(ET)₂X are model systems for studying strongly-correlated charge carriers and the Mott metal-insulator transition in reduced dimensions. Conducting layers of ET molecules are separated by thin, insulating anion layers X, resulting in a quasi-2D electronic band structure. The ET molecules are arranged in dimers forming a triangular lattice. One free charge carrier exists per dimer, its spin being geometrically frustrated. The Mott insulator κ-(ET)₂Cu[N(CN)₂]Cl exhibits a gap in the charge-carrying excitations caused by the Coulomb interaction between the electrons and shows antiferromagnetic ordering at T_N≈27 K. Recently, it has been shown that disorder induced by X-ray irradiation drives the Mott insulating state with long-ranged antiferromagnetic order into a quantum spin liquid state [1]. We perform comparative measurements of fluctuation (noise) spectroscopy on pristine and irradiated (disordered) samples in order to investigate the changes in electronic transport mechanism and low-frequency charge carrier dynamics [2] when tuning the Mott insulator to the spin liquid ground state.
T. Furukawa et al., PRL 115, 077001 (2015).
B. Hartmann et al., PRL 114, 216403 (2015).