Aharonov-Bohm ring with a side-coupled atomic cluster: Magnetotransport and the selective switching effect

Abstract

We report electronic transmission properties of a simple tight binding Aharonov-Bohm ring threaded by a magnetic flux, to one arm of which a finite cluster of atoms has been attached from one side. We demonstrate that, by suitably choosing the number of scatterers in each arm of the quantum ring, the transmission across the ring can be completely blocked when the ring is decoupled from the atomic cluster and the flux threading the ring becomes equal to half the fundamental flux quantum. A novel transmission resonance then occurs immediately as the coupling between the ring and the impurity cluster is switched 'on'. It is shown that the delta-like transmission resonances occur precisely at the eigenvalues of the side coupled chain of atoms. The 'switching' effect can be observed either for all the eigenvalues of the isolated atomic cluster, or for a selected set of them, depending on the number of scatterers in the arms of the ring. The ring-dot coupling can be gradually increased to suppress the oscillations in the magneto-transmission completely. However, the suppression can lead either to a complete transparency or no transmission at all, occasionally accompanied by a reversal of phase at special values of the magnetic flux.

Controlled electron transport in coupled Aharonov–Bohm rings

“…(12) implies that, for the entire range of energy for which F (E) remains bounded by ±1, one can easily fix up a value of the secondary flux Φ S such that the transmission across the primary ring is unity, as discussed elsewhere [26]. In the simple case of the (4, 3) system, the function F (E) remains within ±1 for all values of the energy E within (ǫ 0 − 2t 0 , ǫ 0 + 2t 0 ), i.e.…”

“…The bulk sites of the primary ring are then decimated to convert the P-S ring system into an effective 'diatomic molecule' A − B clamped between the leads ( Fig.1(b)). The effective on-site potentials at A and B and the renormalized flux dependent hopping integral between them are given by [26],…”

Impurity-modified Fano effect in a double quantum dot Aharonov–Bohm interferometer

“…[2][3][4] Meanwhile, the relevant theoretical investigations involve various QD structures, for example, one or two QDs embedded in an Aharonov-Bohm ͑AB͒ interferometer, [5][6][7][8][9][10] double QDs in different coupling manners. [11][12][13] According to these theoretical results, the Fano effect in QD structures exhibits some peculiar behaviors in electronic transport process, in contrast to the conventional Fano effect.…”

Even-odd parity oscillations in spin polarization of a quantum dot array

“…Recently, many experimental and theoretical works have become increasingly concerned about the electronic transport through various QD arrays. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] For example, specific odd-even parity oscillations of the conductance have been discussed for systems of an embedded QD array [11][12][13][14][15][16] and of a QD array side-coupled to a quantum wire 3 or an Aharonov-Bohm ͑AB͒ ring. 17 Xu 5 has presented a method for the calculations of electron transport in multiterminal QD array systems based on real-space lattice models.…”

“…[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] For example, specific odd-even parity oscillations of the conductance have been discussed for systems of an embedded QD array [11][12][13][14][15][16] and of a QD array side-coupled to a quantum wire 3 or an Aharonov-Bohm ͑AB͒ ring. 17 Xu 5 has presented a method for the calculations of electron transport in multiterminal QD array systems based on real-space lattice models. Very recently, due to the emergence of spintronics, the spinpolarized transport in QDs has attracted considerable attention both theoretically [20][21][22][23][24][25][26][27][28][29] and experimentally.…”