Quantum transport in open mesoscopic cavities

Bird, J. P.; Ishíbashi, K.; Aoyagi, Yoshinobu; Sugano, Takuo; Akis, R.; Ferry, D. K.; Pivin, David P.; Connolly, Kevin M.; Taylor, R. P.; Newbury, R.; Olatona, D.M.; Micolich, A. P.; Wirtz, R.; Ochiai, Y.; Okubo, Yasushi

doi:10.1016/s0960-0779(97)00021-0

Cited by 31 publications

(28 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The details of the oscillations are found to be related to the recurrence with gate voltage of strongly scarred wave function states, whose features are sensitive to the lead configuration in the dots. We discuss these results in terms of the influence of the lead openings on electron transport in open dots.Here we summarize the results of studies of more than ten different split-gate dots, whose fabrication has been described elsewhere [6]. We focus, in particular, on the behavior exhibited by two dots with different lead configurations (see Fig.…”

mentioning

confidence: 99%

“…1). The transport properties of these GaAs͞AlGaAs dots were measured in a dilution refrigerator, at a fridge temperature of 10 mK and using small constant currents with lockin detection [6]. From measurements at this temperature, the wafer mobility and carrier density were determined and were found to be 4 3 10 15 m 22 and 70 m 2 ͞V s, respectively.…”

mentioning

confidence: 99%

“…Here we summarize the results of studies of more than ten different split-gate dots, whose fabrication has been described elsewhere [6]. We focus, in particular, on the behavior exhibited by two dots with different lead configurations (see Fig.…”

mentioning

confidence: 99%

“…An upper-bound estimate of the number of electrons in the dots is therefore of the order of 100-400, for the same range of gate voltage. Another parameter inferred from magnetotransport studies was the electron phase breaking time ͑t f ͒, which was of the order of 100 ps at the low temperatures of interest here [6].…”

mentioning

confidence: 99%

“…From measurements at this temperature, the wafer mobility and carrier density were determined and were found to be 4 3 10 15 m 22 and 70 m 2 ͞V s, respectively. The effective size of the dots was estimated from the period of AharonovBohm oscillations in the edge state regime [6] and varied from 0.2 0.3 mm, depending on the value of the applied gate voltage. An upper-bound estimate of the number of electrons in the dots is therefore of the order of 100-400, for the same range of gate voltage.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Lead-Orientation-Dependent Wave Function Scarring in Open Quantum Dots

et al. 1999

Self Cite

View full text Add to dashboard Cite

Experimental studies of the conductance of open quantum dots show a series of highly regular oscillations at low temperatures as the voltage applied to their defining gates is varied. Simulations of quantum transport through these dots reveal the oscillations to be correlated to the recurrence of specific groups of wave function scars. We furthermore find that nominally identical dots, differing only in the orientation of their input and output contacts, may be used to excite different families of scars, giving rise in turn to measurable transport results. [S0031-9007(99)09319-9] PACS numbers: 73.23. Ad, 85.30.Vw Semiconductor quantum dots, consisting of a submicron sized cavity and quantum point contact leads, are ideally suited for studying the influence of environmental coupling on the discrete level spectrum of quantum systems. Of particular interest here is the nature of electron transport in open dots, whose leads are configured to support a small number of propagating modes. While it is often argued that the level spectrum is continuous in such dots, recent studies have instead emphasized the role that the leads play in selectively exciting discrete dot states during transport [1][2][3][4][5]. In this Letter, we consider the sensitivity of this selection process to the nature of the coupling that is provided between the dot and its external environment. Splitgate dots with different lead orientations are fabricated and their transport properties are measured at low temperatures. When the voltage applied to their defining gates is varied, a series of regular oscillations is observed in the conductance, providing a unique signature of the couplinginduced modifications that arise in the level spectra of the dots. The details of the oscillations are found to be related to the recurrence with gate voltage of strongly scarred wave function states, whose features are sensitive to the lead configuration in the dots. We discuss these results in terms of the influence of the lead openings on electron transport in open dots.Here we summarize the results of studies of more than ten different split-gate dots, whose fabrication has been described elsewhere [6]. We focus, in particular, on the behavior exhibited by two dots with different lead configurations (see Fig. 1). The transport properties of these GaAs͞AlGaAs dots were measured in a dilution refrigerator, at a fridge temperature of 10 mK and using small constant currents with lockin detection [6]. From measurements at this temperature, the wafer mobility and carrier density were determined and were found to be 4 3 10 15 m 22 and 70 m 2 ͞V s, respectively. The effective size of the dots was estimated from the period of AharonovBohm oscillations in the edge state regime [6] and varied from 0.2 0.3 mm, depending on the value of the applied gate voltage. An upper-bound estimate of the number of electrons in the dots is therefore of the order of 100-400, for the same range of gate voltage. Another parameter inferred from magnetotransport studies was the electron ph...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Lead-Orientation-Dependent Wave Function Scarring in Open Quantum Dots

et al. 1999

Self Cite

View full text Add to dashboard Cite

show abstract

Open quantum dots: Physics of the non‐Hermitian Hamiltonian

Ferry

Akis

Burke

et al. 2012

Fortschritte der Physik

Self Cite

View full text Add to dashboard Cite

Quantum dots provide a natural system in which to study both classical and quantum features of transport, as they possess a very rich set of eigenstates.When coupled to the environment through a pair of quantum point contacts, these dots possess a mixed phase space which yields families of closed, regular orbits as well as an expansive sea of chaos. In this latter case, many of the eigenstates are decohered through interaction with the environment, but many survive and are referred to as the set of pointer states. These latter states are described by a projected, non-Hermitian Hamiltonian which describes their dissipation through many-body interactions with particles in the external environment.

show abstract

Is it the boundaries or disorder that dominates electron transport in semiconductor `billiards'?

Micolich¹,

See²,

Scannell³

et al. 2012

Fortschritte der Physik

Self Cite

View full text Add to dashboard Cite

Key words quantum chaos, semiconductor billiards, quantum dots, ballistic transport Semiconductor billiards are often considered as ideal systems for studying dynamical chaos in the quantum mechanical limit. In the traditional picture, once the electron's mean free path, as determined by the mobility, becomes larger than the device, disorder is negligible and electron trajectories are shaped by specular reflection from the billiard walls alone. Experimental insight into the electron dynamics is normally obtained by magnetoconductance measurements. A number of recent experimental studies have shown these measurements to be largely independent of the billiards exact shape, and highly dependent on sample-tosample variations in disorder. In this paper, we discuss these more recent findings within the full historical context of work on semiconductor billiards, and offer strong evidence that small-angle scattering at the sub-100 nm length-scale dominates transport in these devices, with important implications for the role these devices can play for experimental tests of ideas in quantum chaos.

show abstract

Quantum transport in open mesoscopic cavities

Cited by 31 publications

References 62 publications

Lead-Orientation-Dependent Wave Function Scarring in Open Quantum Dots

Lead-Orientation-Dependent Wave Function Scarring in Open Quantum Dots

Open quantum dots: Physics of the non‐Hermitian Hamiltonian

Is it the boundaries or disorder that dominates electron transport in semiconductor `billiards'?

Contact Info

Product

Resources

About