1 Department of Physics, State Key Laboratory of Surface Physics, and Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China;
2 Polar Research Institute of China, Shanghai 200136, China;
3 School of Information Science and Technology, East China Normal University, Shanghai 200062, China
Based on a first-principles approach, we establish an alternating-current (AC) relaxation theory for a rotating metallic particle with complex dielectric constant εα = εα-σα/ω0. Here εα is the real part, σα the conductivity, ω0 the angular frequency of an AC electric field, and i=√-1. Our theory yields an accurate interparticle force, which is in good agreement with the existing experiment. The agreement helps to show that the relaxations of two kinds of charges, namely, surface polarized charges (described by εα) and free charges (corresponding to σα), contribute to the unusually large reduction in the attracting interparticle force. This theory can be adopted to determine the relaxation time of dynamic particles in various fields.
Project supported by the National Natural Science Foundation of China (Grant No. 11222544), the Fok Ying Tung Education Foundation (Grant No. 131008), the Program for New Century Excellent Talents in University, China (Grant No. NCET-12-0121), and the National Key Basic Research Program of China (Grant No. 2011CB922004).
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