The University of Bath is inviting applications for the following PhD project supervised by Dr Enrico Da Como in the Department of Physics.
Living in the age of information technology and data storage there is an imminent need for new solid state materials capable of storing information and/or performing computational tasks by writing and erasing information in the form of quantum states and with low energy consumption. In the search for memory materials with applications in new disruptive technologies, two-dimensional (2D) transition metal dichalcogenides (TMDs) are in a dominant position, because of their unique electronic band structure, the easy interfacing with device architectures and graphene-based platforms, combined with established preparation procedures.
Semi-metallic TMDs are known to exhibit a plethora of electronic phases where strong electronic interactions drive ordered phases such as charge density wave (CDW) instabilities, superconducting charge pairing, topologically induced gaps and Mott metal-insulator states. The research in our group has so far been focussed on the fundamentals of these electronic ordered states and the possibility to control them using laser light [1,2] or electric fields in field-effect structures [3].
In this project we aim at exploring and understanding the CDW dynamics in the Tantalum based TMDs: TaS2, TaSe2 and in particular the mixed compound TaS2-xSex. The motivation comes from recent preliminary data from our laboratory showing that at defined stoichiometries the mixed compound has a unique hysteric behaviour in the electric resistivity as a function of temperature. While this holds promise for real applications in memories, it also opens a number of interesting questions on the energetic landscape of the CDW and other co-existing or competing electronic phases. By definition CDW are macroscopic quantum states where electrons group into waves with the same periodicity of the lattice, which is distorted with respect to its original above the transition structure. For the tantalum based compounds in focus here, it is the degree of commensurability that sometimes defines new CDW states and possibly an energy landscape with shallow minima and quantum jamming effects [4].
The objectives of the PhD research program consist in 1) design of mixed compounds TaSxSe1-x with optimal quantum memory effects, 2) investigation of electron dynamics by means of quantum transport measurements: resistivity, Hall effect, AC capacitance, 3) study of the electronic structure with optical and photoemission techniques (ARPES) and investigation of incommensurability, 4) demonstration of write/erase control using temperature, electric fields or laser light on prototype memory devices.
This PhD project will offer you the opportunity to learn about spectroscopic methods (lab- and synchrotron-based) aiming at understanding the electronic structure, combined with studies on electronic devices and theoretical models of band structure. You will join the University of Bath physics department where a strong research focus on TMDs is established. The supervisory team has expertise in the different areas and is already collaborating on these materials through the Centre for Doctoral Training in Condensed Matter Physics [5]. The proposed experience for PhD students is thus covering the research fields of quantum electronic transport at low temperatures and spectroscopy of quantum materials.
Candidate requirements:
Applicants should hold, or expect to receive, a First Class or good Upper Second Class Honours degree (or the equivalent) in Physics or Electrical/Materials Engineering, with experience of experimental projects. A master’s level qualification would also be advantageous.
Non-UK applicants will also be required to have met the English language entry requirements of the University of Bath.
Enquiries and applications:
Informal enquiries are welcomed and should be directed to Dr. Enrico Da Como, [Email Address Removed]
Formal applications should be made via the University of Bath’s online application form for a PhD in Physics.
Please refer to our website for more information about how to apply.
Further information:
On our website, you will also find information about tuition fees, understanding your fee status and how to estimate your living expenses in Bath.
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