Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 44: Poster Session Correlated Electrons

TT 44.58: Poster

Donnerstag, 17. März 2011, 10:00–13:00, P1

Doping effects on the non-linear transport in blue bronze — •Ali Al-Hadeethi¹, Duminik Grund¹, Song Yue², Martin Dressel², and Christine Kuntscher¹ — ¹Experimentalphysik II, Universität Augsburg, 86159 Augsburg, Germany — ²Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany

When low-dimensional metals are cooled, they often undergo a phase transition to an insulating state exhibiting a new type of order. A famous example is the blue bronze K_0.3MoO₃, which undergoes a Peierls transition at T_P≈180 K to a charge-density-wave (CDW) state. In this work, the temperature dependence of the dc resistivity and the non-linear transport properties in pure, Rb-doped, and W-doped blue bronze single crystals is presented. Our measurements show that substituting K by Rb and Mo by W shifts T_P to lower values and smears out the metal-insulator transition. At temperatures below T_P nonlinear conductivity due to charge transport by the CDW is observed, when the applied electric field exceeds the so-called first threshold field. The temperature dependence of the first threshold field is presented for all studied samples. Furthermore, the temperature dependence of the second threshold field, which is usually attributed to the onset of coherent CDW sliding, is discussed.