Probing Spin Effects in Two-Dimensional Materials Similar to Graphene - Physics & Astronomy - EPSRC DTP funded PhD Studentship Ref: 2904

About the award

This project is one of a number funded by the Engineering and Physical Sciences Research Council (EPSRC) Doctoral Training Partnership to commence in September 2018. This project is in direct competition with others for funding; the projects which receive the best applicants will be awarded the funding.

The studentships will provide funding for a stipend which is currently £14,553 per annum for 2017-2018. It will provide research costs and UK/EU tuition fees at Research Council UK rates for 42 months (3.5 years) for full-time students, pro rata for part-time students.

Please note that of the total number of projects within the competition, up to 15 studentships will be filled.

Supervisors
Dr Annette Plaut
Prof Mikhail (Misha) Portnoi

Location 
Streatham Campus, Exeter

Project Description
The possibility of using the spin of electrons to achieve faster and more energy efficient electronic devices is a central concept of spintronics and  thus spintronic effects are interesting from the perspective of quantum computing. However the lack of an effective means for the successful generation, manipulation and electrical detection of the electron spin within semiconductors remains an outstanding challenge.

Graphene is a two-dimensional honeycomb structure of carbon atoms. However due to the small size of the carbon atom, graphene does not exhibit measurable spintronic effects. Instead graphene is now being superseded by other two-dimensional materials such as the transition metal dichalcogenides, where the honeycomb lattice is made up of, for instance, a combination of a transition metal atom and two sulphur or selenium atoms. The larger inherent spin-orbit interaction in such transition metal dichalcogenides, due to the large size of the transition metal atom, combined with their crystal inversion asymmetry – unlike graphene – make spintronic effects detectable in these new two-dimensional materials.

Spin-orbit coupling is the most fundamental spin-dependent interaction in non-magnetic semiconductors. It is a relativistic  effect that couples the charge-carrier spin to its orbital momentum. In the spin Hall effect, on passing a current through the sample, the spin-orbit interaction drives the charge carriers with up and down spins to opposite sides of the sample. Here it is the intrinsic spin-orbit coupling that causes the charge carriers to move transverse to the current, rather than an external magnetic field as in the classical Hall effect. However the spin Hall effect is not electrically detectable due to the charge-balanced nature of its transverse spin currents. But by optically polarizing the charge carrier spins, the transverse current becomes charge-imbalanced and a Hall voltage can be measured in the absence of a magnetic field.

This EPSRC PhD studentship will fund you to investigate manifestations of the spin Hall effect, and also the closely-related valley Hall effect, via such optically-polarized phototransport techniques. You will search for the elusive spin Hall effect in these two-dimensional materials and confirm the tentative evidence for the existence of the valley Hall effect. You will also be the first ever to measure the carrier-density dependence of such photo-induced voltages. The valley Hall effect arises due to the bandstructure of such two-dimensional materials possessing two unequal valleys at the Dirac points. The spin polarization of the charge carriers is coupled to the valley in which they reside. It is theoretically predicted that photoexcitation of the charge carriers with  linearly-polarized light will result in the carriers belonging to the two different valleys moving in opposite directions. This you will detect purely optically, by measuring the spatial distribution of the circularly-polarized photoluminescence in two-dimensional materials.

During your PhD you will join the vibrant Exeter University Graphene Centre encompassing state-of-the-art facilities and training opportunities providing you with a wide variety of highly employable skills and techniques

Entry Requirements

You should have or expect to achieve at least a 2:1 or above in your BSc or MPhys, or an MSc,  or equivalent, in Physics. 

If English is not your first language you will need to meet the English language requirements and provide proof of proficiency. Click here for more information and a list of acceptable alternative tests.
 

The majority of the studentships are available for applicants who are ordinarily resident in the UK and are classed as UK/EU for tuition fee purposes.  If you have not resided in the UK for at least 3 years prior to the start of the studentship, you are not eligible for a maintenance allowance so you would need an alternative source of funding for living costs. To be eligible for fees-only funding you must be ordinarily resident in a member state of the EU.  For information on EPSRC residency criteria click here.

Applicants who are classed as International for tuition fee purposes are NOT eligible for funding. International students interested in studying at the University of Exeter should search our funding database for alternative options.

Summary

Application deadline:10th January 2018
Value:3.5 year studentship: UK/EU tuition fees and an annual maintenance allowance at current Research Council rate. Current rate of £14,553 per year.
Duration of award:per year
Contact: Doctoral Collegepgrenquiries@exeter.ac.uk

How to apply

You will be required to upload the following documents:
•       CV
•       Letter of application outlining your academic interests, prior research experience and reasons for wishing to
        undertake the project.
•       Transcript(s) giving full details of subjects studied and grades/marks obtained.  This should be an interim
        transcript if you are still studying.
•       If you are not a national of a majority English-speaking country you will need to submit evidence of your current
        proficiency in English.  For further details of the University’s English language requirements please see
        http://www.exeter.ac.uk/postgraduate/apply/english/.

The closing date for applications is midnight (GMT) on Wednesday 10 January 2018.  Interviews will be held at the University of Exeter in late February 2018.

If you have any general enquiries about the application process please email: pgrenquiries@exeter.ac.uk.
Project-specific queries should be directed to the supervisor.

During the application process, the University may need to make certain disclosures of your personal data to third parties to be able to administer your application, carry out interviews and select candidates.  These are not limited to, but may include disclosures to:

• the selection panel and/or management board or equivalent of the relevant programme, which is likely to include staff from one or more other HEIs;
• administrative staff at one or more other HEIs participating in the relevant programme.

Such disclosures will always be kept to the minimum amount of personal data required for the specific purpose. Your sensitive personal data (relating to disability and race/ethnicity) will not be disclosed without your explicit consent.