| Project/Area Number |
59540204
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
物性一般（含極低温･固体物性に対する理論）
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
KANAMORI Junjiro Professor, Faculty of Science, Osaka University, 理学部, 教授 (10028079)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TONEGAWA Takashi Associate Professor, Faculty of Science, Kobe University, 理学部, 助教授 (80028167)
IGARASHI Jun-ichi Assistant, Faculty of Science, Osaka University, 理学部, 助手 (20127179)
|
|---|
| Project Period (FY) |
1984 – 1986
|
| Project Status |
Completed (Fiscal Year 1986)
|
| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1985: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1984: ¥1,200,000 (Direct Cost: ¥1,200,000)
|
|---|
| Keywords | Lattice gas model / Method of inequalities / Surface reconstruction / Surface of semiconductors / Ordered alloys / The (7x7) state / 表面相転移 |
|---|
| Research Abstract |
We analyze superlattice structures of alloys and surface reconstructions with lattice gas models with competing interactions of extended range including more-than-two particle ones. After determining rigorously the model generating given superstructures by use of the method of inequalities developed by the present investigator, we study systematics of the structures of related systems and finite temperatures phases. We aimed primarily at the (7x7),(2x8) and (5x5) reconstruction of the (111) surface of Si, Ge and related systems. We have shown that the lattice gas model on a triangular lattice can generate successivrely these superlattice structures of adatoms with a common set of interaction parameters with varying particle concentration; we pointed out thus a close relation among these structures for the first time. In parallel with this research, however, Takayanagi has proposed a model for the (7x7) state of Si in which three surface layers are reconstructed. This model which was de
… More
duced from various experiments has been definitely confirmed recently by the STM-CITS experiment. Extending, therefore, our analysis to the Takayanagi model, we combine the abovementioned analysis of the triangular lattice gas with the previous one of the honeycomb lattice gas carried out by the present investigator, since the second layer atomic configuration can be represented by the latter, while the third layer reconstruction can be included by a renormalization of the interactions on the top two layers. From the analysis we conclude that the Takayanagi model has a sound basis and can solve a few problems raised by the analysis of the simple triangular lattice model. We predicted then a possible atomic configuration of the (2x8) state of Ge and also that of the disorodered states at high temperatures of both Si and Ge. We are collaborating with experimental groups to study the short range order at high temperatures. We are also preparing for computer simulation calculation to investigate the high temperature behavior of the system.
Another project which was proposed but delayed by the unexpected development of the surface problem is to compile superstructures of fcc and bcc lattice gases with appropriate range of interaction. We shall continue this project in future. Less
|
