title: A Ge/Si heterostructure nanowire-based double quantum dot with integrated charge sensor.
abstract: One proposal for a solid-state-based quantum bit (qubit) is to control coupled electron spins on adjacent semiconductor quantum dots. Most experiments have focused on quantum dots made from III-V semiconductors; however, the coherence of electron spins in these materials is limited by hyperfine interactions with nuclear spins. Ge/Si core/shell nanowires seem ideally suited to overcome this limitation, because the most abundant nuclei in Ge and Si have spin zero and the nanowires can be chemically synthesized defect-free with tunable properties. Here, we present a double quantum dot based on Ge/Si nanowires in which we can completely control the coupling between the dots and to the leads. We also demonstrate that charge on the double dot can be detected by coupling it capacitively to an adjacent nanowire quantum dot. The double quantum dot and integrated charge sensor serve as an essential building block to form a solid-state qubit free of nuclear spin.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Yongjie
authors.initials: Y
authors.lastname: Hu
authors.forename: Hugh O H
authors.initials: HO
authors.lastname: Churchill
authors.forename: David J
authors.initials: DJ
authors.lastname: Reilly
authors.forename: Jie
authors.initials: J
authors.lastname: Xiang
authors.forename: Charles M
authors.initials: CM
authors.lastname: Lieber
authors.forename: Charles M
authors.initials: CM
authors.lastname: Marcus
mesh_terms: D004559:Electric Wiring / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D005857:Germanium / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation* / Q000639:trends; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D045663:Quantum Dots; D011789:Quantum Theory; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry*; D055672:Static Electricity; D018511:Systems Integration; D014159:Transducers
chemical_list: D005857:Germanium; D012825:Silicon