Dresden 2017 – wissenschaftliches Programm
CPP 30.10: Vortrag
Mittwoch, 22. März 2017, 12:00–12:15, HSZ 201
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. Recently, the influence of quenched disorder attracted considerable attention. Conducting layers of ET molecules are separated by thin, insulating sheets with anions X, resulting in a quasi-2D electronic band structure. Within the ET layers the 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 shows antiferromagnetic ordering at TN≈27 K. It has been shown that increasing disorder induced by X-ray irradiation drives the Mott insulating state with long-ranged antiferromagnetic order into a quantum spin liquid state . Here, we discuss comparative measurements of fluctuation spectroscopy on pristine and irradiated samples in order to investigate the changes in electronic transport mechanism and low-frequency charge carrier dynamics  when tuning the Mott insulator to the spin liquid ground state. This results in a decrease of both resistivity and the current or voltage fluctuations after irradiation.
 PRL 115, 077001 (2015)
 PRL 114, 216403 (2015)