论文标题
VO2中的动力学脱钩电和结构相变
Kinetically Decoupled Electrical and Structural Phase Transitions in VO2
论文作者
论文摘要
二氧化钒（VO2）引起了其近室温绝缘子向金属过渡和相关结构相变的极大关注。温度诱导的绝缘子对金属和VO2中伴随的结构相变的基础物理尚未完全了解。我们已经在电阻率测量和拉曼光谱学的帮助下研究了VO2的上述相变行为的动力学。电阻热滞后缩放缩放和温度诱导的绝缘体对金属过渡的弛豫测量揭示了这种一阶相变的异常行为，而拉曼弛豫测量结果表明，温度诱导的VO2中的结构相转变遵循了常规的行为，并且与平均现场预测是一致的。在较高的温度扫描速率下，绝缘子向金属过渡和结构相变的脱钩。 VO2中观察到的异常一级相变行为归因于非常规的准粒子动力学，即显着降低了整个绝缘体到金属转变的电子热导电率，这是由超快光泵 - 孔隙型时间域的热域热触及率测量确认的。
Vanadium dioxide (VO2) has drawn significant attention for its near room temperature insulator to metal transition and associated structural phase transition. The underlying Physics behind the temperature induced insulator to metal and concomitant structural phase transition in VO2 is yet to be fully understood. We have investigated the kinetics of the above phase transition behaviors of VO2 with the help of resistivity measurements and Raman spectroscopy. Resistance thermal hysteresis scaling and relaxation measurements across the temperature induced insulator to metal transition reveal the unusual behaviour of this first-order phase transition, whereas Raman relaxation measurements show that the temperature induced structural phase transition in VO2 follows usual behaviour and is consistent with mean field prediction. At higher temperature sweeping rates decoupling of insulator to metal transition and structural phase transition have been confirmed. The observed anomalous first order phase transition behavior in VO2 is attributed to the unconventional quasi particle dynamics, i.e. significantly lowered electronic thermal conductivity across insulator to metal transition, which is confirmed by ultrafast optical pump-probe time domain thermoreflectance measurements.
