| 학회 |
한국재료학회 |
| 학술대회 |
2011년 가을 (10/27 ~ 10/29, 신라대학교) |
| 권호 |
17권 2호 |
| 발표분야 |
B. Nanomaterials and Processing Technology(나노소재기술) |
| 제목 |
Metal-insulator Transition in (Sr0.75, La0.25)TiO3 Ultra-thin Films |
| 초록 |
The (Sr0.75, La0.25)TiO3 (SLTO) ultra-thin films with various thicknesses have been grown on Ti-O terminated SrTiO3(100) substrate using Laser-Molecular Beam Epitaxy (Laser MBE). By monitoring the in-situ specular spot intensity oscillation of reflection high energy electron diffraction (RHEED), we controlled the layer-by-layer film growth. The film structure and topography were verified by atomic force microscopy (AFM) and high resolution thin film x-ray diffraction by the synchrotron x-ray radiation. We have also investigated the electronic band structure using x-ray absorption spectroscopy (XAS). The ultra thin SLTO film exhibits thickness driven metal-insulator transition around 8 unit cell thickness when the film thickness progressively reduced to 2 unit cell. The 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 drive the metal-insulator transition along with Anderson Localization. In optical conductivity, we have found the spectral weight transfer from coherent part to incoherent part when the film thickness was reduced. This result indicates the possibility of enhanced electron correlation in ultra thin films. |
| 저자 |
Jaedu Choi1, Euiyoung Choi2, Yunsang Lee1, Jaichan Lee2
|
| 소속 |
1School of Advanced Materials Science and Engineering, 2Sungkyunkwan Univ. |
| 키워드 |
SLTO; metal-insulator transition; thin film
|
| E-Mail |
|
