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Development of Scanning Tunneling Microscope Operated under High Pressure Environments

高压环境下扫描隧道显微镜的研制

基本信息

批准号：
09555101
负责人：
KAI Shoichi
金额：
$ 7.36万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

The aim of this research project is to develop a scanning tunneling microscope (STM) capable to be easily handled under super high pressure environments and to study on interfacial phase transition through STM observation of molecular alignments of liquid crystal monolayers as well as their alignment structures. The results obtained are following.(1) The improvement of a high pressure STM and the realization of its operation under 600 MPa were done.(2) The molecular alignments of CィイD260ィエD2 and CィイD270ィエD2 were directly observed with STM under 350MPa. Although phase transitions (PHs) of bulk phase of CィイD260ィエD2 and CィイD270ィエD2 were observed near 350MPa based on previous studies, PHs of the monolayers were not observed at least by 400MPa(3) The systematic observations were carried out for the molecular alignments of homologous series in monolayers of n-cyanobiphenyle (nCB) and n-alkyloxy-cyanobiphenle (nOCB) liquid crystals on highly oriented pyrolytic graphite (HOPG) and molybdenum d … More isulfide (MoSィイD22ィエD2) substrates using scanning tunneling microscope (STM), as well as two-phase mixtures of n-CB. In nCB with n=odd number, only the single row alignments in the monolayer was observed. The monolayer alignments of nCB with n=even on the other hand showed double row characteristics. For nOCB these tendencies were opposite, that is, single tow for n=even and double row for n=odd. Thus all the observed aspects clearly indicated the odd-even effect of carbon numbers in alkyl chains. The origin of the even-odd effect is due to the orientation of prana-zigzag planes of alkyl-chains in nCB and nOCB, which is perpendicular to the substrate plane. The odd-even effect is therefore strongly related to the strength of interactions with substrates through such an orientation. In nCB and nOCB for n=odd, the end carbon atom of an alkyl-chain must be free from and rigid substrates respectively. That is the interaction for n=even in nCB (nOCB) is stronger (weaker) than that for n=odd. This difference leads to basically two different alignments, I.e., the single and double rows. The proposed model has been verified by computer simulation Less

本研究项目的目的是开发一种能够在超高压环境下轻松操作的扫描隧道显微镜（STM），并通过STM观察液晶单层的分子排列及其排列结构来研究界面相变。所得结果如下。(1)对一台高压STM进行了改进，实现了在600 MPa下的操作。(2)在350 MPa压力下，用STM直接观察了C_（60）D_（260）D_（270）的分子排列。虽然基于先前的研究，在350 MPa附近观察到C_（60）D260_（60）D2和C_（60）D270_（60）D2的体相相变（PH），（3）系统地观察了n-氰基联苯（nCB）和n-烷氧基氰基联苯（nOCB）单分子膜中同系列分子的排列情况。高取向热解石墨（HOPG）和钼电极上的液晶 ...更多信息使用扫描隧道显微镜（STM），以及n-CB的两相混合物，在三硫化物（MoS_xD 22_xD 2）衬底上进行。在n=奇数的nCB中，仅观察到单层中的单行排列。另一方面，具有n=偶数的nCB的单层排列显示出双行特性。对于nOCB，这些趋势相反，即对于n=偶数，单丝束和对于n=奇数，双行。因此，所有观察到的方面都清楚地表明了烷基链中碳数的奇偶效应。奇偶效应的起源是由于在nCB和nOCB中的烷基链的prana-zigzag平面的取向，这是垂直于衬底平面。因此，奇偶效应与通过这种取向与基底的相互作用强度密切相关。在nCB和nOCB（n=奇数）中，烷基链的末端碳原子必须分别不含刚性底物和刚性底物。即nCB中n=偶数时的相互作用（nOCB）比n=奇数时的相互作用强（弱）。这种差异导致基本上两种不同的对齐，即，单排和双排。所提出的模型已通过计算机仿真验证Less