Propagation around a Bend in a Multichannel Electron Waveguide

Timp, G.; Baranger, Harold U.; deVegvar, P. G. N.; Cunningham, J. E.; Howard, Richard; Behringer, R. E.; Mankiewich, P. M.

doi:10.1103/physrevlett.60.2081

Cited by 240 publications

(82 citation statements)

References 13 publications

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“…Longitudinal resistanccs which are negative, not + B Symmetrie, and dependent on the properties of the current and vollagc contacts äs well äs on their Separation; periodic and aperiodic magnetoresistance oscillations; absence of local equilibrium -these are all characterislic features of this transport regime which appear in a most extreme and bare form in the electron focusing geometry. One reason for the simplification offerecl by this geometry is that the current and volfage contacts, being point contacts, are not nearly äs invasive äs the widc Icads in a Mall bar geometry [14]. Another reason is that the electrons interact with only one boundary (insteacl of two in a narrow channel).…”

Section: Introdnclionmentioning

confidence: 99%

Coherent electron focusing

Beenakker

Houten

Wees

1989

Advances in Solid State Physics

198

326

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Summnry: Thcory and cxpcrimcnl arc rcvicwcd οΓ Ihc clussical and quantum mcchanical focusing by a niagncüc fickl of ballislic clcctrons injcctcd tlirough a point contact in a Uvo-dimcnsional electron gas. Two altcrnalivc poinLs of vicw arc cmphasizcd. On thc onc band, thc cxpcrimcnL i s n rcalizntion ofclcclron oplics in Ihc solid stalc. Thc thrcc basic building blocks arc a cohcicnt and monochromalic point sourcc/dctcctor, an elcctrostalic mirror wilh littlc diffuse scatlcring, and a magnclic Icns. On thc othcr band, cohcrent clcclron focusing is a rcsislancc mcasurcmcnl in thc quantum ballistic transport rcgime, which cxhibits Ihc charactcristic featurcs of this rcgime in a most extreme way. For cxamplc, largc magnclorcsi.stancc oscillations occur (up to 9.5% amplitudc modulalion is obscrvcd), with a pcriodicily which is non-locally dclcrmincd by thc Separation bctwccn currcnl and vollage point contacLs. Λ WKB calculation of Ihc liansmission probabililics shows lliat Ihis cffect is thc rcsult of thc intcrfcrcncc of cohcrcnlly cxcitcd magnctic edgc slalcs al the electron gas boundary, Anothcr cxamplc is thc abscncc of local cquilibrium: Thc mcasurcmcnts shovv that thc point conlacts can sclectivcly populatc (and clelcct) specific Land au Icvcls, and that Ihis highly non-cquilibrium population is mainlaincd ovcr dislances of microns.

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Section: Introdnclionmentioning

confidence: 99%

Coherent electron focusing

Beenakker

Houten

Wees

1989

Advances in Solid State Physics

198

326

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“…To verify the relatively long elastic mean-free path independently, we have used electronbeam lithography and wet etching to fabricate cross junctions for bend resistance measurements. 16 At room temperature, 100 nm cross junctions indeed display negative bend resistance, 17 which can be destroyed by magnetic focusing in a perpendicular magnetic field, further confirming the ballistic transport. 18 The operation of YBS requires lateral electric field.…”

mentioning

confidence: 49%

Quantum steering of electron wave function in an InAs Y-branch switch

Jones

Yang

et al. 2005

Applied Physics Letters

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We report experimental results on gated Y-branch switches made from InAs ballistic electron waveguides. We demonstrate that gating modifies the electron wave functions as well as their interference pattern, resulting in anticorrelated oscillatory transconductances. Our data provide evidence of steering the electron wave function in a multichannel transistor structure. © 2005 American Institute of Physics. ͓DOI: 10.1063/1.1867554͔ Quantum effects in nanostructures provide insights into fundamental issues that cannot be addressed in atomic physics settings and offer perspectives for future applications in computing. 1 In the regime where quantum effects dominate, electron transport exhibits different properties. For example, when the device size becomes less than the elastic mean-free path, electrons can traverse through the conductor ballistically, leading to conductance quantization. In addition, phase coherent transport plays an important role in nanometer-scale devices. Among devices exploiting these quantum effects, the Y-channel transistor is attractive on its own right. The original proposal of the Y-channel transistor, or Y-branch switch ͑YBS͒ ͑Ref. 2͒ came from an electron wave analogy to the fiber optic coupler. The semiconductor version of YBS has a narrow electron waveguide patterned into a "Y" configuration with one source and two drain terminals. A lateral electric field perpendicular to the direction of electric current in the source waveguide steers the injected electron wave into either of the two outputs. YBS offers several advantages as a fast switch as evidenced by THz ͑Refs. 3 and 4͒ operation of quantum point contacts ͑QPC͒. Most interestingly, in the case of single mode occupation, the switching can be accomplished by a voltage of the order of ប͑e t ͒, where t is the transit time of electrons. 5 With a proper design, the switching voltage for a YBS can become smaller than the thermal voltage, k B T / e, as opposed to 40-80 times of k B T / e needed for the current transistors. Here, k B is the Boltzmann constant and T is the absolute temperature. Switching at low voltages would make such devices less noisy and consume less power, though at the expense of speed. 6

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“…Olhcr anomalies arc: thc last Hall plateau (Roukes et al, 1987;Timp et al, 1987;Simmons et al, 1988;Ford et al, 1988;Chang et al, 1988;, reminisccnt of quanlum Hall platcaus, but occurring at much lower ficlds; thc negative Hall resistance (Ford et al, 1989a), äs if thc carricrs wcre holcs rathcr than clccüons; Ihc bend resistance (Takagaki et al, 1988;I989b;Timp et al, 1988;, a longitudinal resistance associated with a currenl bcnd, which is negative at small magnetic ficlds and zcro al largc ficlds, with an ovcrshoot to a positive valuc at intcrmediatc ficlds; and morc.…”

Section: Introductionmentioning

confidence: 99%