Coulomb localization and exchange modulation in two-electron coupled quantum dots

作     者：Dmitriy V. Melnikov Jean-Pierre Leburton Ahmed Taha Nahil Sobh 

作者机构：Beckman Institute for Advanced Science and Technology & Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign 401 North Mathews Avenue Urbana Illinois 61801 USA National Center for Supercomputing Applications University of Illinois at Urbana-Champaign 1205 West Clark Street Urbana Illinois 61801 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2006年第74卷第4期

页      面：041309(R)-041309(R)页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

摘      要：A general study of the singlet-triplet energy separation (exchange energy) in the two-electron system confined in a realistic double-quantum-dot system is performed using a hybrid multiscale approach where the many-body Schrödinger equation is solved exactly within the full quantum dot device environment. The exchange energy is computed as a function of the gate confinement and magnetic field. In particular, it is found that at zero magnetic field the exchange energy varies from meV to sub-μeV values as the confinement gate biases (tunneling barrier) are changed and the system is driven from a single quantum dot to two coupled quantum dots. The small values of the exchange coupling in this structure are attributed to the large interelectron separation arising when the Coulomb repulsion dominates tunneling.