Nanoscale spin rectifiers controlled by the Stark effect.The control of orbitals and spin states of single electrons is a key ingredient for quantum information processing and novel detection schemes and is, more generally, of great relevance for spintronics.  Coulomb and spin blockade in double quantum dots enable advanced single-spin operations that would be available even for room-temperature applications with sufficiently small devices.  To date, however, spin operations in double quantum dots have typically been observed at sub-kelvin temperatures, a key reason being that it is very challenging to scale a double quantum dot system while retaining independent field-effect control of individual dots.  Here, we show that the quantum-confined Stark effect allows two dots only 5 nm apart to be independently addressed without the requirement for aligned nanometre-sized local gating.  We thus demonstrate a scalable method to fully control a double quantum dot device, regardless of its physical size.  In the present implementation we present InAs/InP nanowire double quantum dots that display an experimentally detectable spin blockade up to 10 K. We also report and discuss an unexpected re-entrant spin blockade lifting as a function of the magnetic field intensity.
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