| Project/Area Number |
11640338
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
固体物性Ⅱ(磁性・金属・低温)
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
FUKUYAMA Hidetshohi Institute for Solid State Physics, Professor, 物性研究所, 教授 (10004441)
|
|---|
| Project Period (FY) |
1999 – 2002
|
| Project Status |
Completed (Fiscal Year 2002)
|
| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
|
|---|
| Keywords | organic conductors / quarter-filled bands / electronic properties / localized spins / magnetite / metal-insulator transition / Verwey / Verwey転移 / 磁気秩序 / 超交換相互作用 / マグネタイイト / Vervey転移 / 低次元有機導体 / 分子間クーロン相互作用 / ハートリーフォック近似 / モット絶縁体 / 電荷秩序状態 / ハイゼンベルグスピン模型 / スピンギャップ |
|---|
| Research Abstract |
Theoretical studies on the charge ordering and associated electronic properties in quarter-filled bands are developed. Especially organic conductors with localized magnetic ions, i.e. π・d systems, and magnetites, the typical magnetic systems, are pursued in details.
The formers are of interest in view of the fact that biological molecules with functionality have often localized spins, while the latter attracts general interest since the understanding is far from complete in spite of the first proposal by Verwey half a century ago.
In the π・d systems, the spatial pattern of the magnetism of localized spins is directly coupled with that of the charge disproportionation of the π electrons leading to a unique feature of metal-insulator transition.
On the other hand, the charge ordering scenario for the metal-insulator transition in magnetites has recently been challenged by the careful NMR measurement. In this research project, a new and completely different mechanism for the metal ・ insulator transition in magnetites has been proposed based on the orbital ordering and accompanying Peierls transition of spinless fermions moving along the one-dimensional direction. This proposal has stimulated renewed efforts in the experimental activities.
|
