MAGDOPREF: High field magneto-spectroscopy of single dopants in semiconducting nanowires using RF reflectometry
Research project selected under the 2013 call for proposals
Principal Investigator :
Mathieu PIERRE ()
LNCMI (Groupe nano-objets et nanostructures semiconductrices)
Type of project : Disruptive Project
Date (start/end) : 2014 - 2016
Schematics of the RF reflectometry measurement setup.
Abstract
The goal of the project is to investigate atomic-like systems in semiconductors under high magnetic field, with a particular focus to individual dopant atoms in silicon. These systems are promising candidates for the realization of spin quantum bits. Their orbital states are expected to be strongly modified by high magnetic fields of the order of several tens of Teslas, as the charge bound to the dopants undergoes magnetic confinement. Magneto-transport spectroscopy will be performed on single dopants in silicon nanowire transistors, in which an electrical current flows through the dopant orbitals at low temperature in the subthreshold regime. The measurement of the transport properties of the devices under pulsed magnetic field requires the measurement of small and fast-varying currents, which cannot be performed with usual DC measurement techniques. Therefore, we work towards the development under pulsed, high magnetic field of radio-frequency (RF) reflectometry, which has the required bandwidth and sensitivity. It consists in measuring the dissipation in an LC oscillator embedding the high impedance nano-device. The experimental challenge lies in making this technique compatible with the pulsed magnetic field environment. We expect that new insights will emerge from the combination of several extreme experimental conditions: small quantum objects cooled at low temperature will undergo a very high magnetic field while being electrically probed at high frequency.
The project is carried out by the nano-object and semiconducting nanostructure group of the high magnetic field laboratory (LNCMI) in Toulouse. The project benefits from its expertise at addressing individual nano-devices for electrical measurements at low temperature and under pulsed, high magnetic field. The new RF setup built in this project may be used for the study of various nano-devices. It will also be crucial in the race towards measurements at higher magnetic field, for instance using the new 80T and 90T developed at LNCMI, as the pulse duration becomes shorter when the magnetic field reached increases. The setup may be open for external users of the LNCMI facilities.