Development of scanning tunneling microscope under multiple extreme conditions and study of electronic phases in organic conductors

2014 Fiscal Year Final Research Report

• Project/Area Number: 24654095
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Hokkaido University
• Principal Investigator: ICHIMURA Koichi 北海道大学, 工学(系)研究科(研究院), 准教授 (50261277)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 走査トンネル顕微鏡 / 高圧 / 有機導体 / 電荷秩序 / 強相関電子系

Outline of Final Research Achievements

A scanning tunneling microscope (STM) under high pressure and low temperature was developed. The electronic state of organic conductors, which are materials with the highly correlated electron system, were studied by STM. The role of the long range Coulomb interaction was discussed.
STM measurements were performed on three organic conductors with the alpha-type donor arrangement, in which the system tends to undergo the charge ordering state. The charge disproportionation with a stripe structure was found at high temperature in three salts irrespective of its ground states. Moreover, the stripe pattern varied depending on the anisotropy of the electronic band structure. The results suggest that a dimerization has an important role in forming the charge ordering as well as the long range Coulomb interaction. The finding obtained by the present study contributes to elucidate the origin of the charge ordering state, which characterizes highly correlated electron systems.

Free Research Field

電子物性物理学