ac electric and magnetic responses of nonconnected Aharonov-Bohm rings
ac electric and magnetic responses of nonconnected Aharonov-Bohm rings
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DOI：
10.1103/physrevb.65.075301
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发表时间：
2002-02-15
影响因子：
3.7
通讯作者：
Mailly, D
中科院分区：
文献类型：
--
作者：
Deblock, R;Noat, Y;Mailly, D
在20 mK和500 mK之间，用共振方法在350 MHz下测量了10（5）个非连接的Aharonov-Bohm环的电磁响应的相位相干性特征。在GaAs-AlxGa 1-xAs异质结中蚀刻环。这两个量都表现出振荡行为，其周期性与环中通量量子Phi（0）/2=h/2 e的一半一致。我们发现，电屏蔽增强时，时间反演对称性被打破的磁场，导致一个积极的磁极化率，在有限频率的孤立环的理论预测一致。温度和电子密度的依赖关系进行了研究。电响应的耗散部分，电吸收，也被测量，并导致负的磁导。同样的环的磁轨道响应也进行了研究。这与0.25 nA的抗磁持续电流一致。这种磁响应比电响应小一个数量级，与理论预期定性一致。
The signature of phase coherence on the electric and magnetic response of 10(5) nonconnected Aharonov-Bohm rings is measured by a resonant method at 350 MHz between 20 mK and 500 mK. The rings are etched in a GaAs-AlxGa1-xAs heterojunction. Both quantities exhibit an oscillating behavior with a periodicity consistent with half a flux quantum Phi(0)/2=h/2e in a ring. We find that electric screening is enhanced when time-reversal symmetry is broken by magnetic field, leading to a positive magnetopolarizability, in agreement with theoretical predictions for isolated rings at finite frequency. Temperature and electronic-density dependences are investigated. The dissipative part of the electric response, the electric absorption, is also measured and leads to a negative magnetoconductance. The magnetic orbital response of the very same rings is also investigated. It is consistent with diamagnetic persistent currents of 0.25 nA. This magnetic response is an order of magnitude smaller than the electric one, in qualitative agreement with theoretical expectations.