2006 Fiscal Year Final Research Report Summary
Electronic structure and phonons of low-dimensional metals prepared on crystal surfaces
| Project/Area Number |
16340090
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | Kyoto University |
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Principal Investigator |
ARUGA Tetsuya Kyoto University, Chemistry Department, Professor, 大学院理学研究科, 教授 (70184299)
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| Co-Investigator(Kenkyū-buntansha) |
OKUYAMA Hiroshi Kyoto University, Chemistry Department, Associate Professor, 大学院理学研究科, 助教授 (60312253)
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| Project Period (FY) |
2004 – 2006
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| Keywords | surface / phase transition / charge density wave / angle-resolved photoemission / 相転移 |
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| Research Abstract |
In low-dimensional metals, the effects interactions, such as electron-electron and electron-phonon ones, plays significant roles to give rise to intriguing phenomena such as density waves and superconductivity. Photoelectron spectroscopy provides single-particle spectral functions and hence serves as a powerful technique in low-dimensional physics. The aim of this work was to study electronic properties of low-dimensional structures prepared on surfaces by angle-resolved photoelectron spectroscopy (ARPES) and to study phonon dispersion of such materials by ultrahigh resolution electron energy loss spectroscopy (UREELS), and eventually to reveal the mechanisms of new and interesting phenomena at surfaces. The Fermiology and the temperature dependence of a CDW gap on In/Cu(001) CDW system exhibited weak-coupling-like appearance, which however contradicted with other qualitative characteristics of the phase transition. We therefore measured the critical X-ray scattering during the phase transition. By analyzing the lattice correlation length above the 2D Ising transition and comparing it with the CDW correlation length obtained by ARPES, we have succeeded in categorizing the phase transition to a strong-coupling, long-coherence type, which usually was not known. This is the most significant achievement of this work. We also studied the magnetism of ultrathin Mn-Pd surface alloys and novel phase transition in Bi monolayer on Ag(001) driven by vacancy-configuration entropy. During the latter study, we found a giant Rashba spin-orbit splitting in Bi/Ag(001), which is nearly an order of magnitude larger than those previously known. The study of this phenomenon is currently under way.
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