Surface Acoustic Phonon and Dirac Quasiparticle Coupling in Strong Spin Orbit Semiconductors

This PhD project will address this challenge by developing a non-contact surface acoustic wave technique to access quantum spin Hall states. Building on our recent significant success in inducing acoustoelectric currents in Bi2Se3 thin films for the first time worldwide, the student will design and fabricate high-frequency surface acoustic wave devices using pairs of Inter-Digital Transducers on LiNbO3 substrates to probe the two-dimensional (2D) quantum spin Hall states. This will involve cleanroom lithography, thin-film growth optimisation, and characterisation methods including X-ray reflectivity and diffraction, surface morphology studies using atomic force microscopy, Raman spectroscopy, scanning tunnelling microscopy, THz spectroscopy and low-temperature magnetotransport (including use of the new Bragg 12T HiCaLM dilution refrigerator Facility and 16T PPMS with helium 3 cryostat). Our innovative approach will provide fundamental insights into surface phonon–quasiparticle interactions and pave the way for the next-generation spintronic and quantum technologies.<br /> <br /> Seven decades ago, the semiconductor industry revolutionised technology through the first implementation of integrated circuits, transforming modern life. Half a century later, the discovery of strong spin-orbit coupling in semiconductors opened new frontiers in electronics by enabling control of spin degrees of freedom to provided added functionality without external magnetic fields. The spin-orbit coupling has thereafter become a cornerstone for spintronics and almost all current quantum technologies, offering pathways to future energy-efficient, high-speed devices.<br /> <br /> Today, materials with strong spin-orbit coupling are recognised as the key building blocks for quantum spin Hall systems, which exhibit Dirac-like surface states with linear energy dispersion. The exotic quasiparticles which define transport in these systems promise low-loss energy electronics by suppressing backscattering. However, conventional electrode-based techniques for probing these states often degrade their properties, posing a significant challenge for device development.

<p>To apply for this project you will need to make a formal application for research degree study through the <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">University website</a>. You will need to create a login ID with a username and PIN. </p> <p>•    For <strong>Application type</strong> please select <strong>Research Degrees – Research Postgraduate</strong>. <br /> •    The admission year for this project is <strong>2027/28</strong> Academic Year. <br /> •    You will need to select your <strong>Planned Course of Study</strong> from a drop-down menu. For this project, scroll down and select <strong>PHP Physics & Astronomy Full Time.</strong> <br /> •    The project start date for this project is <strong>1 October 2027</strong>, please use this as your <strong>Proposed Start Date of Research</strong>. <br /> •    Please state clearly in the<strong> Research Information Section</strong> that the research degree you wish to be considered for is <strong>Surface Acoustic Phonon and Dirac Quasiparticle Coupling in Strong Spin Orbit Semiconductors</strong> as well as <a href="https://eps.leeds.ac.uk/physics/staff/4131/dr-satoshi-sasaki?_gl=1*lgoozr*_gcl_au*NDIyMzgwMjgxLjE3NjM0MTMwNTE.*_ga*MTIzODQ2OTE0OC4xNzYzNDEzMDUx*_ga_SEKE21EBEQ*czE3NjYwOTkxNTYkbzckZzEkdDE3NjYwOTk5MTEkajQ3JGwwJGgxODcwNTA3ODc3#journal_article_div">Dr Satoshi Sasaki</a> as your proposed supervisor.</p> <p><strong>Please state clearly in the Finance section</strong>, <strong>the funding that you are applying for, if you are self-funding or externally sponsored</strong>.</p> <p>More information on how to apply is available on our website <a href="https://www.leeds.ac.uk/research-applying/doc/applying-research-degrees">here</a>. You will be required to provide a personal statement which outlines your interest in the project you are applying for, why you have chosen it and how your skills map onto the requirements of the project.</p> <p>We will assess applications continuously as we receive them. We welcome and strongly encourage any potential applicants to contact the supervisor(s) for an informal discussion, prior to applying, and recommend submitting your application early.</p> <p><strong>If you are applying with external sponsorship or you are funding your own study, please ensure you provide your supporting documents at the point you submit your application:</strong></p> <ul> <li>Full Transcripts of all degree study or if in final year of study, full transcripts to date including the grading scheme</li> <li>Personal Statement outlining your interest in the project</li> <li>CV</li> </ul> <p>If English is not your first language, you must provide evidence that you meet the University'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>

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>This is a non funded PhD project. Applicants are expected to be self funded or to secure external funding.</p> <p>You can find out more about our Funding Opportunities on our <a href="https://phd.leeds.ac.uk/">Postgraduate Research Opportunities</a> website.</p> <p><strong>Important: </strong>Please note that all costs associated with your arrival at Leeds (<a href="https://www.leeds.ac.uk/international-visas-immigration/doc/applying-student-visa">visa, Immigration Health Surcharge</a>, flights etc) would have to be met by yourself, or you will need to find an alternative funding source.</p>

<p>For questions related to the application process and eligibility, please contact PGR Admissions by email to <a href="mailto:epspgradmissions@leeds.ac.uk">epspgradmissions@leeds.ac.uk</a></p> <p>For further information about this project, please contact Dr Satoshi Sasaki by email to <a href="mailto:S.Sasaki@leeds.ac.uk">S.Sasaki@leeds.ac.uk</a></p>