Theory of ferroelectric polarization control in hydrogen-bonded organic ferroelectric system

2016 Fiscal Year Final Research Report

• Project/Area Number: 25400334
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: IWANO Kaoru 大学共同利用機関法人高エネルギー加速器研究機構, 物質構造科学研究所, 研究機関講師 (10211765)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 光誘起相転移 / 水素結合型強誘電体 / 分極反転

Outline of Final Research Achievements

In this project, we investigated two topics, that are, photoinduced ferroelectric polarization disappearance in the croconic acid and the determination of polarization in α-(BEDT-TTF)2I3. Regarding the first topic, we applied a quantum chemical method to a molecular cluster and estimated the maximum number of polarization inversion in units of molecules as about ten. Furthermore, we also clarified possible paths to realize such polarization inversion. Regarding the second topic, we found both spin-polarized and spin-unpolarized solutions. Based on the former solution, we calculated the direction of the polarization and found that the result is consistent with the observation. The spin-unpolarized solution, on the other hand, does not reproduce the experimental result. Meanwhile, it shows a Dirac-electron feature,being a physically interesting system. We proposed a new scheme to calculate the polarization and succeeded in determining it accurately.

Free Research Field

光物性