2006 Fiscal Year Final Research Report Summary
Investigation of electronic structure and electron conduction mechanism of InN
| Project/Area Number |
17560293
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Electronic materials/Electric materials
|
|---|
| Research Institution | TOKAI UNIVERSITY |
|---|
Principal Investigator |
INUSHIMA Takashi Tokai University, School of Information Science and Technology, Professor, 情報理工学部, 教授 (20266381)
|
|---|
| Project Period (FY) |
2005 – 2006
|
| Keywords | Superconductivity of InN / Fermi surface / Electron Localization / Critical current |
|---|
| Research Abstract |
Temperature dependence of the resistivity of InN was investigated as a function of carrier density. The carrier density was changed from n_e=1.8x10^<18>cm^<-3> to 1.5x10^<19>cm^<-3> by Si doping. The InN investigated showed metallic conduction above 20 K. At lower temperatures there was a resistivity anomaly originating from carrier localization in the a-b plane, which was confirmed by the magnetoresistance at 0.5 K. The Shubnikov de-Haas oscillation showed that InN had a spherical Fermi surface and its radius increased according to the increase of ne when n_e<5x10^<18>cm^<-3>. In addition an oscillation corresponding to the constant carrier density of 4.5x10^<12>cm^<-2> was observed in the field applied perpendicular to the a-b plane. This oscillation showed an anomalous angle dependence on the magnetic field. Taking into account this density, we determined the critical carrier density of the Mott transition to be 2x10^<17>cm^<-3>. Anisotropy of localization was observed within the a-b plane, which indicates that the distribution of the electrons was not uniform in the a-b plane. From these results, an electronic structure at the fundamental absorption edge of InN grown on sapphire (0001) was presented.
On the other hand, samples with carrier densities n_e as low as 4x10^<17>cm^<-3> show superconductivity with T_c= 0.47 K (midpoint). As in the layered cuprate high Tc superconductors, the vortex solid of InN is melted by thermal fluctuation and by the external magnetic field. The field dependence of the critical current J_c exhibits an exponential decay over a wide range of magnetic field, which is ascribed to the current tunneling through micro Josephson-junctions. We propose a mechanism where the anisotropy of J_c is related to the presence of In-In chains of finite length in the ab plane.
|
Research Products
(14 results)
-
-
[Journal Article] Superconductivity of InN as an intrinsic property2007
Author(s)
T.Inushima, N.Kato, D.K.Maude, H.Lu, W.J.Schaff, R.Tauk, Y.Meziani, S.Ruffenach, O.Briot, B.Gil, H.Miwa, A.Yamamoto, D.Muto, Y.Nanishi
-
Journal Title
AIP Conf. Proc 893
Pages: 137-138
Description
「研究成果報告書概要(和文)」より
-
-
[Journal Article] Superconductivity of InN as an intrinsic property2007
Author(s)
T.Inushima, N.Kato, D.K.Maude, H.Lu, W.J.Schaff, R.Tauk, Y.Meziani, S.Ruffenach, O.Briot, B.Gil, H.Miwa, A.Yamamoto, D.Muto, Y.Nanishi
-
Journal Title
AIP Conf.Proc. 893
Pages: 137
Description
「研究成果報告書概要(欧文)」より
-
-
-
-
-
[Journal Article] Superconductivity of InN with a well defined Fermi surface2006
Author(s)
T.Inushima, N.Kato, D.K.Maude, H.Lu, W.J.Schaff, R.Tauk, Y.Meziani, S.Ruffenach, W.Knap, O.Briot, B.Gil, H.Miwa, A.Yamamoto, D.Muto, Y.Nanishi
-
Journal Title
Phys. Stat. Sol. (b) 243
Pages: 1679-1686
Description
「研究成果報告書概要(和文)」より
-
-
-
[Journal Article] Superconductivity of InN with a well defined Fermi surface2006
Author(s)
T.Inushima, N.Kato, D.K.Maude, H.Lu, W.J.Schaff, R.Tauk, Y.Meziani, S.Ruffenach, W.Knap, O.Briot, B.Gil, H.Miwa, A.Yamamoto, D.Muto, Y.Nanishi
-
Journal Title
Phys.Stat.Sol. (b)243
Pages: 1679-1686
Description
「研究成果報告書概要(欧文)」より
-
-
