检索结果-南通市图书馆

检索条件"主题词=TCNQ compound"

共 1 条记录，以下是1-10 订阅

全选清除本页清除全部题录导出标记到"检索档案"

详细简洁

排序：

Infrared study on pressure induced charge delocalization in Cs2tcnq3

Infrared study on pressure induced charge delocalization in ...

引用

18th International Conference on High Pressure Science and Technology

作者： Hasanudin T.Kagayama N.Kuroda T.Sugimoto Department of Mechanical Engineering and Materials Science Faculty of EngineeringKumamoto UniversityKumamoto 860-0855Japan Department of Mechanical Engineering and Materials Science Faculty of EngineeringKumamoto UniversityKumamoto 860-0855Japan Department of Mechanical Engineering and Materials Science Faculty of EngineeringKumamoto UniversityKumamoto 860-0855 Japan CRESTJapan Science and Technology CorporationKawaguchi 332-0012Japan Research Institute for Advanced Science and Technology Osaka Prefecture UniversitySakai 599-8570Japan

＜正＞Cs2tcnq3 crystallizes into a columnar structure consisting of a periodic stack of tcnq0/tcnq/TCNCT, resulting in a semiconductor with the lowest optical energy gap of 0.3 eV [1]. The radicals tcnq are dimerized, so that the uppermost valence band is formed by the π* orbit of spin singlet. Since the on-site repulsion energy U ≈ 1.2 eV of the π* electrons is higher than the optical energy gap, Cs2tcnq3 may be regarded as a charge-transfer semiconductor of the 1/3-filled Hubbard system. It has been reported that this material undergoes the phase transition to a metallic state at around 3 GPa [2], although the optical energy gap remains unclosed [1]. In the present work, to obtain information about the mechanism of this semiconductor-to-metal transition, we measure the pressure dependence of the infrared molecular vibration. Figure 1 shows the absorption spectra in the C-CN stretching region at several pressures. The features at 1205 and 1211 cm-1 at the ambient pressure arise from neutral and radical molecules, respectively, whereas the one at 1183 cm-1 is the electron-molecular-vibration （e-mv） coupled mode. The former two features show a blue-shift with increasing pressure, while increasing their energy spacing. At around 3.6 GPa they abruptly displace toward each other about half the way of the energy spacing, showing that the π* electrons delocalize significantly from radical to neutral molecules. Evidently this is related to the high electric conductivity at high pressures. It is noteworthy that in the high-pressure phase radical-like and neutral-like molecules still coexist spectroscopically, and thus the π* electrons are not completely delocalized. The frequency, on the other hand, of the e-mv mode remains almost unchanged at low pressures. The e-mv mode disappears above 3.6 GPa, in coincidence with the disappearance of the electronic band S1, which is the counterpart of the e-mv mode [1].

关键词： tcnq compound semiconductor -to- metal transition molecular vibration

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

全选清除本页清除全部题录导出标记到“检索档案”

共1页 << < 1 > >>

回到顶部

执行限定条件

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：