| 학회 |
한국재료학회 |
| 학술대회 |
2008년 봄 (05/22 ~ 05/23, 상록리조트) |
| 권호 |
14권 1호 |
| 발표분야 |
반도체재료 |
| 제목 |
STRAIN SENSITIVITY OF EPITAXIALLY STRAINED SrTiO3 and BaTiO3: FIRST-PRINCIPLE STUDY |
| 초록 |
The effect of epitaxial strain on SrTiO3 (STO) and BaTiO3 (BTO) lattices has been studied by using density functional theory within the local-density approximation. The strain-induced sequence of phase transitions was determined to be c-p-aa for STO and c-r-aa for BTO in a wide range of misfit strain from -2% to +2%. All the transitions are second-order. It was strikingly found that the optical phonon of the strained BTO is characterized by overdamping and reorientation while that of the strained STO shows a perfect softening to zero frequency at the phase boundaries. Consequently, the dielectric constant of BTO shows a significantly low sensitivity to strain in comparison with that of STO. This behavior agrees with the experimentally observed dielectric behavior of Ba-based materials. The origin of this striking difference is attributed to the existence of the order-disorder component in the strain-induced transition mechanism in BTO. |
| 저자 |
P.V. Ong1, Lee JaiChan2
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| 소속 |
1School of Materials Science and Engineering, 2Sung Kyun Kwan Univ. |
| 키워드 |
Dielectric; SrTiO3; phase transition
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| E-Mail |
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