Quantum memory based on charge density wave transition metal chalcogenides

The University of Bath is inviting applications for the following PhD project under the supervision of Dr Enrico Da Como and Prof Daniel Wolverson in the Department of Physics.

Overview of the Project:

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 combined with established synthesis 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 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].

In this project we aim at exploring and understanding the CDW dynamics in the Tantalum based TMDs: 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 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 quantum jamming effects [3].

The objectives of the PhD research program consist in 1) design of mixed compounds TaSxSe1-x with optimal quantum memory effects, 2) study of the electronic structure with optical and photoemission techniques (ARPES) and investigation of incommensurability, 3) 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 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 [1]. 

Project keywords: Transition Metal Dichalcogenides, Charge Density Wave, Quantum Memory, ARPES, Ultrafast Spectroscopy, Crystal Growth, Correlated electron systems.

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 must meet our English language entry requirement.

Enquiries and Applications:

Informal enquiries are welcomed and should be directed to Dr Enrico Da Como (email [Email Address Removed]).

Formal applications should be made via the University of Bath’s online application form for a PhD in Physics.

More information about applying for a PhD at Bath may be found on our website.

Equality, Diversity and Inclusion:

We value a diverse research environment and aim to be an inclusive university, where difference is celebrated and respected. We welcome and encourage applications from under-represented groups.

If you have circumstances that you feel we should be aware of that have affected your educational attainment, then please feel free to tell us about it in your application form. The best way to do this is a short paragraph at the end of your personal statement.