%0 Generic %1 ding2013magnetic %A Ding, J. W. %A Yan, X. H. %A Wang, B. G. %A Xing, D. Y. %D 2013 %K rings %T Magnetic response of mesoscopic rings: a quantum size effect %U http://arxiv.org/abs/1303.1873 %X We analytically study the magnetic response of persistent current (PC) in normally non-interacting mesoscopic rings of bimodal potential with nearest neighboring interactions (t) and alternating site energies. It is shown that a ring of perimeter (N) and width (M) generally shows weak diamagnetic, breaking the even-odd rule of electron filling. Especially, a maximal paramagnetic current in primary F0/2 period is predicted at N=(2p+1)(M+1) with odd M and integer p, while a maximal diamagnetic F0/2- current obtained at N=(2p+1)(M+1)+/-1 with even M. The current amplitudes depend strongly on both N and M, varied by at least 1~2 orders of magnitude, exhibiting a remarkable quantum size effect. A current limit of paramagnetic harmonics is expected at N=2p(M+1), independent of the sizes of N and M, in favor of experiment observation. A new mechanism of magnetic response is proposed that an electron circling the ring shall pass successively each channel within one flux quantum, accumulating an additional phase on each inter-channel transition, which leads to the paramagnetic-diamagnetic transition and period halving. The results unify and unveil the contradictions in PC between theory and experiments, validating quantum mechanics at mesoscopic scale.

@misc{ding2013magnetic, abstract = {We analytically study the magnetic response of persistent current (PC) in normally non-interacting mesoscopic rings of bimodal potential with nearest neighboring interactions (t) and alternating site energies. It is shown that a ring of perimeter (N) and width (M) generally shows weak diamagnetic, breaking the even-odd rule of electron filling. Especially, a maximal paramagnetic current in primary F0/2 period is predicted at N=(2p+1)(M+1) with odd M and integer p, while a maximal diamagnetic F0/2- current obtained at N=(2p+1)(M+1)+/-1 with even M. The current amplitudes depend strongly on both N and M, varied by at least 1~2 orders of magnitude, exhibiting a remarkable quantum size effect. A current limit of paramagnetic harmonics is expected at N=2p(M+1), independent of the sizes of N and M, in favor of experiment observation. A new mechanism of magnetic response is proposed that an electron circling the ring shall pass successively each channel within one flux quantum, accumulating an additional phase on each inter-channel transition, which leads to the paramagnetic-diamagnetic transition and period halving. The results unify and unveil the contradictions in PC between theory and experiments, validating quantum mechanics at mesoscopic scale.}, added-at = {2013-03-11T21:28:41.000+0100}, author = {Ding, J. W. and Yan, X. H. and Wang, B. G. and Xing, D. Y.}, biburl = {https://www.bibsonomy.org/bibtex/2e18a502ada351cb0f5ce5d452df43ccb/vakaryuk}, description = {Magnetic response of mesoscopic rings: a quantum size effect}, interhash = {03c43a495e972f292480471d73435339}, intrahash = {e18a502ada351cb0f5ce5d452df43ccb}, keywords = {rings}, note = {cite arxiv:1303.1873 Comment: 8 pages, 5 figures}, timestamp = {2013-03-11T21:28:42.000+0100}, title = {Magnetic response of mesoscopic rings: a quantum size effect}, url = {http://arxiv.org/abs/1303.1873}, year = 2013 }