標題: Differential conductance of a saddle-point constriction with a time-modulated gate-voltage
作者: Tang, CS
Chu, CS
電子物理學系
Department of Electrophysics
關鍵字: differential conductance;quasi-bound-state;quantum transport;photocurrent
公開日期: 1-Nov-1998
摘要: This work investigates how a time-modulated gate-voltage influences the differential conductance G of a saddle-point constriction. The constriction is modeled by a symmetric saddle-point potential and the time-modulated gate-voltage is represented by a potential of the form V(0)Theta(a/2 - \x - x(c)\) cos(omega t). For h omega less than half of the transverse subband energy level spacing, gate-voltage-assisted (suppressed) feature occurs when the chemical potential mu is less (greater) than but close to the threshold energy of a subband. Our results indicate that as mu increases, G exhibits, alternatively, the assisted and the suppressed feature. For a larger h omega, these two features may overlap. In addition, dip structures are found in the suppressed regime, and mini-steps are found in the assisted regime only when the gate-voltage covers a region sufficiently distant from the center of the constriction. (C) 1998 Elsevier Science B.V. All rights reserved.
URI: http://dx.doi.org/10.1016/S0921-4526(98)00468-2
http://hdl.handle.net/11536/147846
ISSN: 0921-4526
DOI: 10.1016/S0921-4526(98)00468-2
期刊: PHYSICA B
Volume: 254
起始頁: 178
結束頁: 187
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