2004 Fiscal Year Final Research Report Summary
Theoretical study of anomalous electronic states of vanadium oxides with pyroclore lattice structures
| Project/Area Number |
14540324
|
|---|
| 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 | Chiba University |
|---|
Principal Investigator |
OHTA Yukinori Chiba University, Department of Physics, Associate Professor, 理学部, 助教授 (70168954)
|
|---|
| Project Period (FY) |
2002 – 2004
|
| Keywords | strongly correlated electron systems / transition metal oxides / DMRG / spin-triplet superconductivity / orbital ordering / charge ordering / frustration / Hubbard model |
|---|
| Research Abstract |
We have made theoretical and computational studies of strongly correlated electron systems, aiming in particular at elucidation of the mechanisms of the anomalous electronic properties of transition-metal oxides and molecular conductors. We have used the density-matrix renormalization group(DMRG) method for calculating the electronic states of pseudo-one-dimensional models in high accuracy. The main results obtained are the following.
1.We have clarified the mechanism of the charge and orbital ordering of the triangular-lattice Hollandite compound Bi_xV_8O_<16>.
2.We have clarified the mechanism of the orbital ordering and spin-singlet formation in pyroxene compound NaTiSi_2O_6.
3.We have clarified the nature of the anomalous spin excitations that appear in the states of large charge fluctuation.
4.We have elucidated the anomalous charge dynamics in the CuO double-chain systems.
5.We have proposed the novel mechanism of formation of the spin-gap liquid state that appears when the quantum melting of charge-ordered state occurs in the CuO double-chain systems.
6.We have calculated the precise electronic phase diagram of the ground state of the one-dimensional extended Hubbard model.
7.We have proposed the novel mechanism of the spin-triplet superconductivity that appears in the two-chain zigzag-bond Hubbard model.
|
