New Phase Transition Phenomenon in an Organic Molecular Conductor -A Novel Route for an Organic Electronics


 The state of matter dramatically varies with external temperature. For example, water (liquid phase) changes into ice (solid phase) with cooling. Such a phase change is known as the phase transition. Here, water and ice coexist only at 0 degrees centigrade. At the higher temperatures, the liquid phase is realized. On the other hand, at the lower temperatures, the solid phase emerges. The temperature of 0 degrees centigrade is thus the boundary between liquid and solid phases, known as the phase transition temperature. The research group of Nagoya University (Assist. Prof. Ryuji Okazaki and Prof. Ichiro Terasaki in the laboratory of condensed matter physics of functional materials), in collaborations with Dr. Yuka Ikemoto and Dr. Taro Moriwaki in Japan Synchrotron Radiation Research Institute, Prof. Mori’s group in The University of Tokyo, and Prof. Sasaki’s group in Tohoku University, has found that two different electronic states spatially coexist in an organic molecular conductor in a broad temperature range from the phase transition temperature of -200 degrees centigrade nearly to the absolute zero temperature (around -273 degrees centigrade ). This is highly anomalous behavior because a spatially-homogeneous state is usually realized below the phase transition temperature. Such an inhomogeneous state can be sensitively changed by the external field, such as electric field, leading to a possible organic nonlinear device using the inhomogeneous state. 

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