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| Name | Chen,Yiing-Rei |
|---|---|
| Office_Hour | （週一 ）8：00～10:00（週五）8：00～10:00 |
| Office phone number | 02-77496034 |
| Fax | 02-29326408 |
| yrchen@ntnu.edu.tw | |
| Education | Ph. D., State University of New York at Stony Brook, USA |
| Category | Full-Time Faculty |
|---|---|
| Job title | Associate Professor |
| Research Fields | condensed matter physics |
| Research expertise | condensed matter physics |
| Laboratory | / |
Note: The following information may show the name of the Web page owner only.
- Journal papers
- Using both tight-binding model and ab initio calculations, we investigate a system of polyene-bridged armchair carbon nanotube electrodes to address quantum transport through junctions with multiple conjugated molecules. Both one-polyene and two-polyene cases are considered. The ab initio results of the two-polyene cases show the interference effect in transmission and its strong dependence on the configuration of contact sites. This agrees with the tight-binding model. In addition, the discrepancy brought by ab initio relaxation provides an insight into how the junction’s geometry, bonding, and effective potential influence the transmission spectra.。
- What if we played the Rubik’s cube game by simple intuition? We would rotate the cube, probably in the hope of getting a more organized pattern in each next step. Yet frustration occurs easily, and we soon find ourselves trapped as the game progresses no further. Played in this completely strategy-less style, the entire problem of the Rubik’s cube game can be compared to that of complex chemical reactions such as protein folding, only with less guidance in the searching process. In this work we look into this random-searching process by means of thermodynamics and compare the game’s dynamics with that of a faithful stochastic model constructed from the statistical energy landscape theory (SELT). This comparison reveals the peculiar nature of SELT, which relies on the random energy approximation and often chops up energy correlations among nearby configurations. Our observation provides a general insight for the use of SELT in the studies of these frustrated systems.。
- Rigorously speaking, entropy is slightly non-extensive, and this non-extensiveness, which characterizes the degree of fluctuations, can contribute to effective interactions between mesoscopic objects. In this paper, we consider a pair of macroions, each accompanied by 1000 counterions, and with a cell-model description we demonstrate that the slow variation of non-extensiveness in counterion entropy over macroionic distance leads to an effective long-range attraction between the macroions. With the aid of Monte Carlo simulation and a Bragg–Williams theory including counterion number fluctuations, we find the depth of attraction in free energy to be approximately 0.2kBT. The observation in our cell-model study provides an insight for further understanding of effective interactions in real macroionic systems.。
- We study the polarization and electrostatic interactions of an ionic system under geometric confinement in the strong-interacting regime. The geometric confinement is introduced via a simple two-ring model, where ions of each species are confined on a ring, respectively. The observed polarization curve exhibits staircase transitions in the low-temperature regime, due to the crossover between energy local minima. We examine the criterion for the validity of the linear response theory and introduce a simple two-state picture that illustrates the signatures of the crossover phenomena.。
- We present hybrid DFT calculations for large TiO2 cluster models in the gas phase and in solution. Two clusters are investigated, one derived from the anatase bulk structure and the second from rutile. The surfaces are passivated with hydroxyl and water ligands, and continuum solvation is used to model bulk solvent in a subset of calculations. The geometrically optimized bonding patterns, structures, and electronic properties are similar in the two clusters. The distinction between anatase and rutile is minor at this small size. The HOMO and LUMO of the clusters are delocalized, and qualitatively resemble those observed in bulk for both the anatase and rutile derived species. When an additional electron is added, the wave function is again delocalized and there is little change in geometry, and hence minimal polaronic self-trapping. Removal of a surface ligand, creating a defect in that location, does lead to localization of the wave function, but it is unclear whether this actually occurs in real nanocrystalline TiO2 systems. Our results suggest that modeling of electron transport in TiO2 nanocrystal photovoltaic cells may require the presence of electrolyte ions to stabilize localized trapping states.。
- The transmission through prototype aromatic molecule junctions formed between armchair metallic carbon nanotube electrodes is studied using a tight-binding model with a Green’s function embedding approach. Analytical and numerical results for transmission near the Fermi energy are obtained for junctions of single molecules with a one-point contact to each electrode, pairs of such molecules in the junction, and double stranded molecules with a two-point contact to each electrode. While an ideal single stranded molecule ideal polyene with odd number of atoms gives unit transmission at the Fermi energy, two such strands in the junction demonstrate significant interference effects, with net transmission varying from near zero to near 2 depending on the specific contact sites at the electrodes. Ideal polyenes with even number of atoms give nonresonant single-molecule transmission at the Fermi energy and less pronounced interference effects from their double-molecule junctions. The bonded, two stranded junction polyacene also gives nonresonant transmission at the Fermi energy. Allowing for the more realistic bond alternation observed in aromatic molecules results in nonresonant transmission with exponential length dependence。
- Research projects
- 陳穎叡(2015/08/01-2016/07/31)。建構SrxBa1-x(B'1/3B"2/3)O3系列氧化物材料之離子化模型。科技部(原國科會)。(MOST 104-2112-M-003-002-)。主持人。
- 陳穎叡(2010/08/01-2012/07/31)。氧化物系統BaB’2/3B” 1/3O3及CuB2O4之第一原理研究。國科會。(NSC 99-2112-M-003-012-MY2)。主持人。
- 陳穎叡(2008/08/01-2010/07/31)。鋸齒奈米碳管電極間之含氨基分子結的電子傳輸。國科會。(NSC 97-2112-M-003-008-MY2)。主持人。
- 陳穎叡(2006/10/01-2008/07/31)。利用密度泛函方法對鹼鹵鹽類之奈米顆粒及奈米碳管間之分子結作研究及模型化。國科會。(NSC 95-2112-M-003-026-MY2/NSC 95-2120-M-003-003)。主持人。
