Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 11: Focus Session: Single Particle Sources for Electronic Devices II
(Joint session of HL and TT organized by HL)

TT 11.1: Hauptvortrag

Montag, 7. März 2016, 14:45–15:15, H10

Energy- and time-resolved detection of hot single-electron wave packets — •Masaya Kataoka — National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, UK

On-demand semiconductor single-electron sources such as mesoscopic capacitors [1] have enabled an electronic analogy of quantum optics experiments. In further development of this field, the presence of a Fermi sea can present a challenge, causing decoherence due to electron-electron interactions [2]. One solution would be to set electron paths in an intrinsic region, where the conduction-band electrons are absent.

We demonstrate long-range electron transport along depleted edges of a two-dimensional system. A stream of hot electrons are emitted from a quantum-dot pump at ~100 meV above the Fermi energy. Due to a strong magnetic field applied, these electrons travel along the edge defined by shallow etching of the surface, while the background Fermi sea along the edge is depleted by a surface gate that covers the edge.

The transport of the hot-electron wave packets is investigated with energy- and time-resolved detectors [3]. We discuss the measurements of arrival-time distribution measurements with time resolution of < 5 ps, the measurements of edge-state velocity [4], a method to extend LO-phonon scattering length to > 0.5 mm, and how the timing of two-electron emission can be tuned by the shape of pump drive signal.

[1] G. Fève et al., Science 316, 1169 (2007).

[2] V. Freulon et al., Nat. Commun. 6, 6854 (2015).

[3] J. D. Fletcher et al., Phys. Rev. Lett. 111, 216807 (2013).