Magnetic response of a single, isolated gold loop

Chandrasekhar, Venkat; Webb, Richard A.; Brady, Michael; Ketchen, M. B.; Gallagher, W. J.; Kleinsasser, A. W.

doi:10.1103/physrevlett.67.3578

Cited by 774 publications

(660 citation statements)

References 14 publications

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“…On the other hand, the present tight-binding model with all LRH integrals supports extended electronic eigenstates even in the presence of disorder [20], and for this reason persistent currents are not reduced by the impurities. Our results are in good agreement with the experimental observations [14,15].…”

supporting

confidence: 93%

“…Theory and experiment [15] seem to agree only when disorder is weak. However, the amplitudes of the currents in singleisolated-diffusive gold rings [14] were two orders of magnitude larger than the theoretical estimates. This discrepancy initiated intense theoretical activity, and it is generally believed that the electron-electron correlation plays an important role in the disordered diffusive rings [10,11,12], though the physical origin behind this enhancement of persistent current is still unclear.…”

mentioning

confidence: 59%

“…The results of the single loop experiments are significantly different from those for the ensemble of isolated loops. Persistent currents with expected φ 0 periodicity have been observed in isolated single Au rings [14] and in a GaAs-AlGaAs ring [15]. Levy et al [16] found oscillations with period φ 0 /2 rather than φ 0 in an ensemble of 10 7 independent Cu rings.…”

Section: Abstract: Model Calculations Magnetotransportmentioning

confidence: 99%

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Persistent currents with long-range hopping in 1D single-isolated-diffusive rings

2005

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We show from exact calculations that a simple tight-binding Hamiltonian with diagonal disorder and long-range hopping integrals, falling off as a power µ of the inter-site separation, correctly describes the experimentally observed amplitude (close to the value of an ordered ring) and flux-periodicity (hc/e) of persistent currents in single-isolated-diffusive normal metal rings of mesoscopic size. Long-range hopping integrals tend to delocalize the electrons even in the presence of disorder resulting orders of magnitude enhancement of persistent current relative to earlier predictions. Keywords: Model Calculations, MagnetotransportThe phenomenon of persistent current in mesoscopic normal metal rings has generated a lot of excitement as well as controversy over the past years. In a pioneering work, Büttiker, Imry and Landauer [1] predicted that, even in the presence of disorder, an isolated 1D metallic ring threaded by magnetic flux φ can support an equilibrium persistent current with periodicity φ 0 = ch/e, the flux quantum. Later, experimental observations confirm the existence of persistent currents in isolated mesoscopic rings. However, these experiments yield many results that are not well-understood theoretically even today [2,3,4,5,6,7,8,9,10,11,12,13]. The results of the single loop experiments are significantly different from those for the ensemble of isolated loops. Persistent currents with expected φ 0 periodicity have been observed in isolated single Au rings [14] and in a GaAs-AlGaAs ring [15]. Levy et al. [16] found oscillations with period φ 0 /2 rather than φ 0 in an ensemble of 10 7 independent Cu rings. Similar φ 0 /2 oscillations were also reported for an ensemble of disconnected 10 5 Ag rings [17] as well as for an array of 10 5 isolated GaAs-AlGaAs rings [18]. In a recent experiment, Jariwala et al.[19] obtained both φ 0 and φ 0 /2 periodic persistent currents in an array of thirty diffusive mesoscopic Au rings. Except for the case of the nearly ballistic GaAs-AlGaAs ring [15], all the measured currents are in general one or two orders of magnitude larger than those expected from the theory [2,3,4,5,6,7,8,9,10,11,12]. The diamagnetic response of the measured φ 0 /2 oscillations of ensembleaveraged persistent currents near zero magnetic field also contrasts with most predictions [8,9].Free electron theory predicts that at T = 0, an or- * Corresponding author: Santanu K. Maiti E-mail: santanu@cmp.saha.ernet.in dered 1D metallic ring threaded by magnetic flux φ supports persistent current with maximum amplitude I 0 = ev F /L, where v F is the Fermi velocity and L is the circumference of the ring. Metals are intrinsically disordered which tends to decrease the persistent current, and the calculations show that the disorder-averaged current < I > crucially depends on the choice of the ensemble [3,4,5]. The magnitude of the current < I 2 > 1/2 is however insensitive to the averaging issues, and is of the order of I 0 l/L, l being the elastic mean free path of the electrons. This expression...

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supporting

confidence: 93%

mentioning

confidence: 59%

Section: Abstract: Model Calculations Magnetotransportmentioning

confidence: 99%

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Persistent currents with long-range hopping in 1D single-isolated-diffusive rings

2005

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“…The effect has inspired numerous applications in solid state physics [2]. In particular we mention extensive theoretical and experimental research on persistent currents in mesoscopic rings [3,4,5,6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Electron interference in mesoscopic devices in the presence of nonclassical electromagnetic fields

Tsomokos

Chong

Vourdas

2005

J. Opt. B: Quantum Semiclass. Opt.

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Abstract. The interaction of mesoscopic interference devices with nonclassical electromagnetic fields is studied. The external quantum fields induce a phase factor on the electric charges. This phase factor, which is a generalization of the standard Aharonov-Bohm phase factor, is in the case of nonclassical electromagnetic fields a quantum mechanical operator. Its expectation value depends on the density matrix describing the nonclassical photons and determines the interference. Several examples are discussed, which show that the quantum noise of the nonclassical photons destroys slightly the electron interference fringes. An interesting application arises in the context of distant electron interference devices, irradiated with entangled photons. In this case the interfering electrons in the two devices become entangled. The same ideas are applied in the context of SQUID rings irradiated with nonclassical electromagnetic fields. It is shown that the statistics of the Cooper pairs tunneling through the Josephson junction depend on the statistics of the photons.

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“…This is the so-called persistent current, an obvious demonstration of AB effect, and was first proposed by Büttiker et al 8 during early 80's. Following this pioneering work, substantial theoretical and experimental works [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] have been done along this line to understand different aspects of persistent current and other related issues in isolated conducting loops. In particular, the physics of quantum rings has always been the subject of intense research due to its potential applications in designing electronic, spintronic, optoelectronic and information processing devices.…”

Section: Introductionmentioning

confidence: 99%

Magnetic response of non-interacting and interacting electrons in a Möbius strip

Saha

Maiti

2016

Superlattices and Microstructures

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We investigate characteristic features of both non-interacting and interacting electrons in a Möbius strip, the simplest possible one-sided topological system, in presence of an Aharonov-Bohm flux φ. Using Hartree-Fock mean field theory we determine energy eigenvalues for the interacting model, while for the non-interacting system an analytical prescription is given. The interplay between longitudinal and vertical motions of electrons along with on-site Hubbard interaction yield several anomalous features of persistent current associated with energy-flux characteristics. The variation of current with system size and its temperature dependences are also critically examined. Current is highly sensitive to both these two factors, and we find that for a particular system size it decreases exponentially with temperature. Our analysis can be helpful in investigating electronic transport through any non-trivial topological material.

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Magnetic response of a single, isolated gold loop

Cited by 774 publications

References 14 publications

Persistent currents with long-range hopping in 1D single-isolated-diffusive rings

Persistent currents with long-range hopping in 1D single-isolated-diffusive rings

Electron interference in mesoscopic devices in the presence of nonclassical electromagnetic fields

Magnetic response of non-interacting and interacting electrons in a Möbius strip

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