Enhancing Spin Signals in Pure Spin Currents

Excess heat production in modern electronics is a significant problem for improving energy efficiency and sustainability. In conventional electronics this arises from joule heating as electrical charges are moved around the circuit. Another option, however, is to make use of the electron's spin to carry information and to create pure spin currents in which there is no net flow of current. Understanding, controlling and maximising the transmission of electronic spin is key to developing this concept. It turns out that the spin currents can be beneficially influenced by impurities that are deliberately put into the wire, but it matters where the impurities are deposited. This project is part of a large collaboration, Nanoscale advanced Materials Engineering between the Universities of Manchester, leeds and Imperial College, that aims to revolutionise the design and delivery of functionality on demand at the nanoscale within advanced materials. This project will involve a wide range of experimental physics techniques including thin film growth and characterisation, nanofabrication and low temperature electrical measurements. It will suit a student with a strong background in solid state physics or closely related disciplines with an interest in experimental work in a collaborative and team focused environment.

<p style="margin-bottom:24px">Information in most electrical circuits is conveyed by charges that generate heat when they move round the elements of circuit.&nbsp; Reducing the heat in IT systems is now such an important problem that a huge research effort is currently underway to find a solution. Traditionally, cooling has been the way we deal with heat, but this only increases the total energy requirements and so is damaging to the environment and is unsustainable.&nbsp; A better solution would be to avoid generating so much heat in the first place so an alternative to encoding information in charges is a laudable goal. Here we are investigating using a pure spin current that transfers angular momentum (spin) without an accompanying charge current as a means to&nbsp; transfer information without generating Joule heat.&nbsp;</p> <p>In this project we will create pure spin currents by collecting spins at the interface between a ferromagnet and a normal metal.&nbsp; This accumulation of spins generates spin-dependent potentials that drive the spins down the normal metal wire where they can be collected and detected.&nbsp; There is no charge current in the wire because the up- and down-spins flow in opposite directions in equal numbers so there is no net current.&nbsp; It turns out that the spin currents can be beneficially influenced by impurities that are deliberately put into the wire, but it matters where the impurities are deposited.&nbsp;&nbsp;</p> <p>This project is part of a collaboration called&nbsp;<strong><a href="https://name-pg.uk">Nanoscale Advanced Materials Engineering</a>&nbsp;</strong>(NAME),&nbsp;an&nbsp;EPSRC Programme Grant that aims to revolutionise the design and delivery of functionality on demand at the nanoscale within advanced materials.&nbsp; The Universities of Manchester, Leeds and Imperial College and a number of industrial partners have come together to work on an exciting programme of research using the pooled resources and expertise of this world-leading group, enabling us to do more than any single laboratory could achieve.&nbsp; You will work with a number of students and PDRAs not only in Leeds (1 student and 2 PDRAs) but across the collaboration acquiring an enhanced level of knowledge and skills.&nbsp;</p> <p>Central to the project will be the P-NAME tool based in Manchester.&nbsp; It is an atomic level ion implantation instrument with a 20nm resolution and is thus able to deposit impurities with unrivalled precision.&nbsp;&nbsp; We will use impurities deposited in appropriate locations (on the surface, in the centre of the wire, etc) to influence the spin-orbit interaction of electrons in the wire and hence their spin properties.&nbsp; You will grow lateral spin valves (10.1103/PhysRevLett.127.035901, 10.1103/PhysRevB.92.220420) in our bespoke MBE system and learn to make spin current transport measurements as a function of magnetic field and temperatures down to mK.&nbsp; Working with the team in Manchester you will design a doping regime and characterise the impact of the deposition on your samples with the aim of increasing the spin signals in your transport measurements.&nbsp; As a PhD student you will learn advanced materials deposition and characterisation, cleanroom fabrication, and Condensed Matter Physics measurement techniques applicable to a wide range of physics.&nbsp; Our labs are just opening in the new Bragg laboratory at Leeds and are therefore state-of-the-art providing you with an ideal platform to launch your research career.</p> <p style="margin-bottom:24px"><span style="font-size:12pt"><span style="font-family:&quot;Times New Roman&quot;,serif">&nbsp;</span></span></p> <p>&nbsp;</p>

<p>Formal applications for research degree study should be made online through the&nbsp;<a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University&#39;s website</a>. Please state clearly in the Planned Course of Study section that you are applying for <em><strong>PHD Physics &amp; Astronomy</strong></em> and in the research information section&nbsp;that the research degree you wish to be considered for is <em><strong>Enhancing Spin Signals in Pure Spin Currents</strong></em>&nbsp; as well as&nbsp;<a href="https://condensed-matter.leeds.ac.uk/people/gb/">Dr Gavin Burnell </a>and <a href="https://condensed-matter.leeds.ac.uk/people/bjh/">Prof B J Hickey</a> as your proposed supervisor.</p> <p>If English is not your first language, you must provide evidence that you meet the University&#39;s minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p> <p class="MsoNoSpacing">Applications will be considered on an ongoing basis. &nbsp;Potential applicants are strongly encouraged to contact the supervisors for an informal discussion before making a formal application. &nbsp;We also advise that you apply at the earliest opportunity as the application and selection process may close early, should we receive a sufficient number of applications or that a suitable candidate is appointed.</p> <p>Please note that you must provide the following documents in support of your application by the closing date of 5 June 2023:</p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> <li>Funding information:&nbsp; School of Physics &amp; Astronomy</li> </ul>

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.

<p class="MsoNoSpacing">A highly competitive School of Physics &amp; Astronomy Studentship, in support of the&nbsp;<a href="http://name-pg.uk">EPSRC Nanoscale Advanced Materials Engineering</a> Programme grant, consisting of the award of fees at the UK fee rate or Non-UK fee rate of &pound;26,500, with a maintenance grant (currently &pound;17,668 for session 2022/23) for 3.5 years.</p> <p>This opportunity is open to UK applicants only. All candidates will be placed into the School of Physics &amp; Astronomy Studentship Competition and selection is based on academic merit.<br /> <br /> Please refer to the&nbsp;<a href="https://www.ukcisa.org.uk/">UKCISA</a>&nbsp;website for&nbsp;information regarding Fee Status for Non-UK Nationals.</p>

<p>For further information about this project, please contact Dr Gavin Burnell<br /> e:&nbsp;&nbsp;<a href="mailto:g.burnell@leeds.ac.uk">g.burnell@leeds.ac.uk</a></p> <p>For further information about your application, please contact Doctoral College Admissions<br /> e:&nbsp; <a href="mailto:maps.pgr.admissions@leeds.ac.uk">maps.pgr.admissions@leeds.ac.uk</a></p>