| 학회 |
한국재료학회 |
| 학술대회 |
2011년 봄 (05/26 ~ 05/27, 제주 휘닉스 아일랜드) |
| 권호 |
17권 1호 |
| 발표분야 |
B. Nanomaterials and Processing Technology((나노소재기술) |
| 제목 |
Metal-insulator Transition in (Sr0.75, La0.25)TiO3 Ultra-thin films |
| 초록 |
We have made (Sr0.75, La0.25)TiO3 (SLTO) ultra-thin films with various thicknesses on Ti-O terminated SrTiO3(100) substrate using Laser-Molecular Beam Epitaxy (Laser MBE). The specular spot intensity oscillation of reflection high energy electron diffraction (RHEED) was used to in-situ monitor the layer-by-layer growth. Epitaxial growth was verified by atomic force microscopy (AFM) and thin film x-ray scattering by the synchrotron radiation. We have investigated electronic band structure using x-ray absorption spectroscopy (XAS). SLTO thin films with an insulating character showed band splitting in Ti L3-L2 edge XAS spectrum which is attributed to Ti 3d band splitting. This narrow d band splitting could derive the metal-insulator transition along with Anderson Localization. Similar to SLTO bulk material, SLTO thin films exhibited a metallic behavior above the thickness of 8 unit cell. However, SLTO thin films became insulating with a weak localization characteristic as the thickness was reduced below 8 unit cell. It is a signature of metal-insulator transition. In optical conductivity, we have found the spectral weight transfer from coherent part to incoherent part when the film thickness reduced. This result indicates the possibility of electron-electron correlation. |
| 저자 |
최재두1, 최의영1, 이윤상2, 이재찬1
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| 소속 |
1성균관대, 2숭실대 |
| 키워드 |
SLTO; Metal-insulator Transition; Anderson Localization
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| E-Mail |
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