Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 29: Correlated Electrons: Low-dimensional Systems - Materials 2

TT 29.7: Vortrag

Mittwoch, 25. März 2009, 15:45–16:00, HSZ 301

Resistivity investigations on the X-ray irradiated Mott insulator κ-(ET)₂Cu[N(CN)₂]Cl — •Ammar Naji¹, Ulrich Tutsch¹, Michael Lang¹, and Takahiko Sasaki² — ¹Physikalisches Institut, Goethe-Universität Frankfurt (M), SFB/TRR49, D-60438 Frankfurt am Main — ²Institute for Material Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan

The compound κ-(ET)₂Cu[N(CN)₂]Cl is a two- dimensionally structured organic material with a rich pressure vs. temperature phase diagram including paramagnetic and antiferromagnetic Mott-insulating states as well as metallic, semiconducting and superconducting phases, see e.g., [1]. We used X-ray irradiation to induce defects in the material and by this change the charge distribution between anion- and ET-layers. The smaller resistivity of the irradiated samples compared to non-irradiated ones supports this idea [2]. As a consequence, X-ray irradiation may provide a means for doping the Mott-insulator away from half-filling. We will present resistivity data for the temperature range 5 K ≤ T ≤ 60K and pressures up to 50 MPa from which the p-T-phase diagram of X-ray irradiated κ-(ET)₂Cu[N(CN)₂]Cl will be extracted.

[1] S. Lefebvre et al., Phys. Rev. Lett. 85, 5420 (2000)

[2] T. Sasaki et al., J. Phys. Soc. Jpn. 76, 123701 (2007)