Ultrasonic investigation on BEDT-TTF-based superconductors

研究了BEDT-TTF相关CT配合物的晶体生长和物理性质。在晶体生长研究方面，采用电化学氧化法对β-（BEDT-TTF）_2I_3晶体生长进行了原位观察。在生长开始时观察到籽晶的稳定生长，而生长速率随着时间的推移逐渐减慢。的阴离子分子的分布的时间依赖性的测量显示在阳极周围的阴离子浓度的局部减少。在物理性质方面，用超声波测量方法研究了kappa-（BEDT-TTF）_2K（SCN）_4的超导态，并从涡旋态的角度对结果进行了讨论。用超声波测量方法探测了α-（BEDT-TTF）_2KHg（NCS）_4的低温反常态。用反常态载流子的变化解释了实验结果。测量了α-（BEDT-TTF）_2I_3的热导率随温度的变化。

Crystal growth and physical properties of BEDT-TTF related CT complexes were studied. As to the crystal growth study, In situ observation of crystal growth of beta- (BEDT-TTF) _2I_3 by the electrochemical oxidation method was carried out. Stable growth of the seed crystal was observed at the beginning of the growth, while the growth rate was gradually decelerated with passage of time. A measurement of time dependence of the distribution of the anion molecules shows a local decrease in the anion concentration at around the anode. From this, the observed deceleration of the growth could be explained by the shift of the forming location of the charge-transfer complex which is attributed to the decrease of solute concentration.As to the physical properties, the superconducting statewas of kappa- (BEDT-TTF) _2K (SCN) _4 was investigated ultrasonic measurements, and the result was discussed based on the vortex state of this material. The low-temperature anomalous state of alpha- (BEDT-TTF) _2KHg (NCS) _4 was detected by ultrasonic measurements. The results were interpreted by the carrier change in the anomalous state. Thermal conductivity of alpha- (BEDT-TTF) _2I_3 was measured as functions of temperature.