Browsing by Author "Lin, Kao-Chin"

Now showing 1 - 4 of 4

Bias-dependent bandwidth of the conductance in the presence of electron-phonon interaction
(2010-04-01)
Tang, Ying-Tsan
;
Lin, Kao-Chin
;
Chuu, Der-San
;
電子物理學系
;
Department of Electrophysics
We study the electronic transport in the presence of electron-phonon interaction (EPI) for a molecular electronic device. Instead of mean field approximation (MFA), the related phonon correlation function is conducted with the Langreth theorem (LT). We present formal expressions for the bandwidth of the electron's spectral function in the central region of the devices, such as quantum dot (QD), or single molecular transistor (SMT). Our results show that the out-tunneling rate depends on the energy, bias voltage and the phonon field. Besides, the predicted conductance map, behaving as a function of bias voltage and the gate voltage, gets blurred at the high bias voltage region. These EPI effects are consistent with the experimental observations in the EPI transport experiment. (C) 2010 Elsevier Ltd. All rights reserved.
Electron-photon interaction associated with uncertainty-based tunneling in a parallel double quantum dot
(2008-03-01)
Lin, Kao-Chin
;
Chuu, Der-San
;
電子物理學系
;
Department of Electrophysics
The electron-photon interaction associated with the uncertainty based tunneling (EPAUT) in the parallel double quantum dot system is studied. In the considered system, the electron interacts with the single mode detuning quantum photon field, i.e., omega(ph)+Delta=epsilon(2)-epsilon(1), and transits between the quantum dots (QDs). The corresponding characteristic temperature is calculated and compared with the Kondo temperature to recognize the role of the related quantities. There are two energy uncertainties in the considered system. One is the energy difference between the energy of electron-photon interacting quasiparticle and the Fermi energy of the lead. The other is the detuning factor Delta. Besides, vertical bar Delta/pi vertical bar is the bandwidth of the intermediate state of EPAUT. The peak of the density of state corresponding to the EPAUT rises when the temperature is in the order of or below the characteristic temperature. The EPAUT peak can be modified via tuning the Fermi energy of the lead connected to the adjoined QD. Hence, the conductance between the connected leads is varied via tuning the Fermi energy of the lead connected to the adjoined QD.
Influence of phonon-associated tunneling rate on transport through a single-molecule transistor
(2011-01-01)
Tang, Ying-Tsan
;
Chuu, Der-San
;
Lin, Kao-Chin
;
電子物理學系
;
Department of Electrophysics
We study the electronic transport through a single-molecule transistor (SMT) by considering the phonon-associated tunneling rate We find that the electron-phonon interaction (EPI) changes the constant conductivities of the leads into a multi-channel structure of single vibration frequency This interference of the multi-channel tunneling process results in a bias-dependent tunneling rate and obscures the conductance peaks at large bias voltage The bias-dependent tunneling rate further causes a remarkable conductivity gap between the chemical potential of the leads (n = 0) and the first phonon sideband (n = 1) These anomalies are consistent with the experimental observations in transport experiments (C) 2010 Elsevier Ltd All rights reserved
Observation of localized surface plasmons in spatially controlled array structures
(2009-07-29)
Chou, J. W.
;
Lin, Kao-Chin
;
Lee, Yao-Jen
;
Yuan, Chi-Tsu
;
Hsueh, Fu-Kuo
We observed the reflectance spectra of three different nano-scale array structures of Au-coated silicon nanorods. The trends of the reflectance spectra indicate that the localized surface plasmon modes can be spatially controlled by manipulating geometric parameters, namely the lattice constants of the array. In addition, the experimental results were compared with 2D numerical simulations based on the finite element method. Satisfactory agreement between the experimental observations and numerical results was obtained.