PhD: Controlling spins in silicon vacancy defects in diamond.

Project Outline

An electron trapped at a vacancy is essentially a real life example of a particle trapped in a box. The spin state of this system can be manipulated for use as a single photon source or as a qubit in a quantum computer. In diamond the nitrogen vacancy centre contains a vacancy with a trapped electron. The spin state of the nitrogen vacancy can be detected optically which has led to high precision magnetic field imaging and single spin sensors. This system is at the forefront of applications in quantum computing. However, the system has some drawbacks, specifically related to its optical properties. The silicon vacancy is a promising alternative but little is know about its spin physics. In this project I'm investigating the silicon vacancies centres properties with the intention of discovering the fesability of optical control.

This project will bring together electron paramagnetic resonance and optical detection to investigate the spin physics of the system and specifically the optical dependence of the spin polarisation. If the silicon vacancy can be optically controlled it is a candidate for storage and processing of quantum information.

My Background

Before coming to Warwick I studied material science at St Edmund Hall at the University of Oxford (2009 - 2013). My masters project was on iron defects in silicon solar cells. One of the main techniques I used during my masters was electrically detected magnetic resonance (EDMR) which gave me an insight into the world of magnetic resonance and is what inspired me to apply to the Magnetic Resonance Doctoral Training Centre (iMR-CDT) here at Warwick.

During my degree I did two internships. One was at the University of California, Santa Barbara (find out more here) where I made and tested different organic solar cells. The second was at Ruhr-Universität Bochum in Germany where I used density functional theory (DFT) to do materials modelling.

Conferences & Presentations

De Beers Diamond Conference, University of Warwick 11-14th of July, 2016

At this meeting I presented a poster entitled 'Investigating the Energy Levels of Silicon Vacancy Centres in Diamond'.

iMR-CDT Conference, University of Southampton 20 - 23rd March, 2016

This was an opportunity to meet up with the other students in the Centre for Doctoral Training and learn more about how their PhDs where progressing. At this meeting I a gave a presentation about my recent results entitled 'Wavelength Dependence of the Polarisation of Silicon Vacancy Centres'.

Cafe Academique, University of Warwick 20th of Jaunary, 2016

Cafe Academique is a monthly meeting at Warwick which allows postgraduate students from different disciplines to socialise and share their research. I gave a presentation about 'Colour centres in Diamond'.

Physics Seminar, University of Warwick 22nd of October, 2015

I presented my latest findings at the postgraduate physics seminar in a talk called 'Quantum Computing using Diamond'.

De Beers Diamond Conference, University of Warwick 6 - 9th of July, 2015

I presented a poster; 'Towards optically detected magnetic resonance from the neutral silicon vacancy centre in diamond'.

iMR-CDT Conference, University of Warwick 14 - 16th of April, 2015

I presented a poster; 'Properties of Silicon in Diamond measured using Electron Paramagnetic Resonance'.

St Andrews - Dundee EPR Group Meeting, University of Dundee 18th of December, 2014

I did my first presentation about my PhD research; 'The Silicon Vacancy Centre in Diamond'.

De Beers Diamond Conference, University of Warwick 7 - 10th July, 2014

Annual Royal Society of Chemistry Electron Paramagnetic Resonance Meeting, University of Dundee 6 - 10th of April, 2014

Travel

NERC Ion Micro-Probe Facility at University of Edinburgh, 22 - 24th of June, 2016

One of the projects which I'm working on investigates the presence of different ions in diamonds. When diamonds are being made in a high pressure high temperature (HPHT) environment different ions migrate to the surface of the diamond at different speeds. This leads to an uneven distribution of ions. At the secondary ion mass spectroscopy (SIMS) facility at Edinburgh these different ions can be investigated. More information can be found about this excellent facility here.

Takasaki Advanced Radiation Research Institute in Japan, 25th of January - 9th of February, 2015

During my PhD I had the exciting opportunity to visit Takasaki in Japan. As I introduced in my project outline, I'm interested in silicon vacancies in diamond. In order to create these colour centres, vacancies have to be introduced into the diamond. This can be done by electron irradiation, which involves firing high energy electrons at the diamond. In Takasaki there is a facility to do this with high accurately. While visiting Takasaki I also had a chance to meet the very friendly scientists who work at the facility and try many different local foods.

Courses

Women in Science Communication Course - 23rd of June, 2014

This course was designed to help women communicate about the scientific area in which they work. It had various different aspects including telling a story with your science to make it more engaging, methods for explaining a complex story in a way that it can be understood by a general audience and learning how to speak in public with the help of a voice coach. The aim of the meeting was to emphasise the importance of women in science and to communicate this to younger generations. The course was put on by Screenhouse, a company which makes science programmes for TV. Their website and courses can be found here.

Storytelling Techniques and Theatre Training Methods for Scientists - 19th of January, 2016

This course was designed by Dr Andrea Brunello for scientists who wish to improve their public speaking. He is a former physicist who now has a full time professional career in the theatre. By using classical theatre training and storytelling techniques the workshop was aimed at opening up to the public and becoming a better public speaker and communicator. In the process practical exercises were developed; finding one’s centre; increase one’s own awareness; gaining a healthy sense of confidence in the relationship with the others; developing listening skills; improvisation; tempo/rhythm; leadership and courage. During the workshop some time was devoted to proper breathing techniques and voice management to improve stage presence.

At the end of the workshop we each gave an original, engaging presentation of our own work.

Email: s.m-t.g.mottishaw@warwick.ac.uk