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Reference : UPR2940-FLOPOI-039
Workplace : GRENOBLE
Date of publication : Friday, September 11, 2020
Scientific Responsible name : Julien RENARD
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 November 2020
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
The future of nanoelectronics will be quantum. The downscaling in electronics has now reached a point where the size of the devices (less than 10 nm) means that their quantum behavior must be taken into account. While this might be seen by some industries as a major problem this also gives a real opportunity to imagine and build devices with new quantum functionalities.
A key building block for future quantum electronics systems is the quantum bit. Such system has two possible states (0 and 1) that follow the laws of quantum mechanics. One example is that one might build any superposition of 0 and 1. This will have implications for building future quantum computers.
In this PhD project we want to build a new type of device to implement a quantum bit that would have strong advantages over other competing systems. The idea is to use the know-how that has been developed in the superconducting quantum bit community over the past 20 years and integrate in the core of the system a semiconducting material to bring novel electrical functionality to the device, in the form of a voltage-tunable energy. We will use graphene, a two-dimensional zero-band-gap semiconductor, because of the potential scalability of such approach. Such device is expected to behave as a quantum two-level system with an energy structure that can be tuned with an electric field (gate) thanks to graphene.
A one atom-thick sheet of graphene will thus have to be integrated into a superconducting quantum bit design using nanofabrication techniques available at the Institute. Such sample will then be measured at very low temperature (20mK) in a dilution refrigerator using radiofrequency (1-10 GHz) techniques. After the demonstration of the electrical tunability, more advanced measurements will be carried out in the PhD project: lifetime, coherence, coherent manipulation.
The student will be part of the Hybrid team in the Néel Institute, which has a multidisciplinary expertise (growth, nanofabrication, electronic transport, spectroscopy...). The team collaborates with many groups in Grenoble and has also several external collaborations worldwide (France, Switzerland, Germany, Canada). Néel Institute is a basic research laboratory in condensed matter physics, with an additional interdisciplinary expertise at the interfaces with chemistry, engeenering and biology.
The PhD thesis will require a solid background in solid state/condensed matter physics. The work will be mainly experimental. The candidate is expected to be strongly motivated to learn the associated techniques (nanofabrication in clean room, radiofrequency electronics, cryogenics...) and engage in an hands-on experimental work.
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