Layer Number Dependence of Charge Density Wave Phase Transition Between Nearly-Commensurate and Incommensurate Phases in 1T-TaS2
Layer Number Dependence of Charge Density Wave Phase Transition Between Nearly-Commensurate and Incommensurate Phases in 1T-TaS2
复制标题
DOI：
10.1021/acs.jpcc.0c08414
复制
发表时间：
2020-12-10
影响因子：
3.7
通讯作者：
Takai, Kazuyuki
中科院分区：
文献类型：
--
作者：
Ishiguro, Yasushi;Bogdanov, Kirill;Takai, Kazuyuki
通过电阻测量和拉曼光谱研究了 350 K 左右 1T-TaS2 中近等相 (NCCDW) 和不等相 (ICCDW) 之间的电荷密度波 (CDW) 相变。随着层数的减少，NCCDW-ICCDW 相变中的温度滞后 Delta T 减小，这与之前报道的 180 K 左右的相应 CDW (CCDW) 和 NCCDW 相之间的转变形成鲜明对比。不同的 Delta T 趋势可以用不同的起源来解释。 NCCDW-ICCDW 和 CCDW-NCCDW 区域之间 Delta T 层数依赖性的差异主要是由 CCDW 和 ICCDW 相位之间沿面外方向的 CDW 上部结构的差异来解释的。该结果将有助于室温下利用CDW相变的器件应用的开发。此外，建议将低于70 cm(-1)的拉曼光谱基线作为研究CDW转变的常规探针。
The charge density wave (CDW) phase transition between the nearly commensurate (NCCDW) and incommensurate (ICCDW) phases in 1T-TaS2 around 350 K was investigated by electrical resistance measurement and Raman spectroscopy in terms of the number of layers of the samples. Temperature hysteresis Delta T decreases in the NCCDW-ICCDW phase transition as the number of layers decreases, which is in contrast to the transition between the commensurate CDW (CCDW) and NCCDW phases around 180 K, as previously reported. The different Delta T trend can be explained by the different origins. The difference in the layer-number dependence of Delta T between the NCCDW-ICCDW and CCDW-NCCDW region is mainly explained by the difference in the CDW superstructure along the out-of-plane direction between the CCDW and ICCDW phases. The results will be helpful for the development of device applications using CDW phase transition at room temperature. In addition, the baseline of Raman spectra below 70 cm(-1) is proposed as a conventional probe to investigate CDW transitions.