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Accueil du site > Vie du laboratoire > Congrès / Colloques / Conférences > Optical Properties of Individual Nanowires and Quantum Dots in High Magnetic Field, Septembre 2014 > Programme du workshop > Abstract : Stark effect control of the energy spectrum of single and multiple quantum dots in InAs/InP nanowires

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Abstract : Stark effect control of the energy spectrum of single and multiple quantum dots in InAs/InP nanowires

The control of orbital and spin state of single electrons is a key ingredient for spintronics and for the design novel detectors. Coulomb blockade provides a practical tool to manipulate single carriers and scaling is bringing single-electron devices ever closer to non-cryogenic applications. In double dots - the solid-state equivalent of bi-atomic molecules - advanced single-spin manipulations become possible thanks to Pauli spin blockade (SB).

 

In my presentation, I shall review how Stark effect can be used to strongly impact the energy spectrum of a single quantum dot implemented in InAs/InP heterostructured nanowires and tune its blockade characteristics. In particular, I shall show that this technique allows an electrostatic tuning of the energy gaps in our devices and also a control of the spin configuration of the quantum dot ground state [1,2]. Impact on device applications and detection schemes will be discussed.

 

In a second part of the talk, I shall also demonstrate that Stark effect provides a novel and unforeseen method to independently control the filling of two dots at the same time, even if when they are separated only by few nanometers. This allows to measure SB in a nanoscale double dot system, without the need of implementing any challenging nanoscale gating architecture. This approach - thanks to the highly integrated heterostructures possible using InAs/InP nanowires - makes it possible to observe SB up to a temperature of about 10K. An unexpected phenomenology in the Pauli blockade lifting as a function of the magnetic field and possible applications will be discussed.

 

References :

 

[1] S.Roddaro et al. “Manipulation of Electron Orbitals in Hard-Wall InAs-InP Nanowire Quantum Dots”, Nano Lett. 11, (2011).

[2] L.Romeo et al. “Electrostatic Spin Control in InAs-InP Nanowire Quantum Dots”, Nano Lett. 12, 4490 (2012).