PhD Studentship: Ultrafast Control of Valley and Spin Qubits: Engineering and Physical Research Council (EPSRC) Doctoral Training Partnership

The University of Exeter is offering up to 9 fully funded doctoral studentships for September 2024 entry as part of our Doctoral Training Partnership with the EPSRC (Engineering, Physical Sciences Reserach Council).

The University of Exeter offers a world-class education and research in one of the most beautiful locations in the UK. As a Russell Group University our research makes a difference across the world and we’re committed to working with our PhD researchers to make the world greener, healthier, and fairer.  Our Doctoral College stimulates, supports and sustains a vibrant research and intellectual environment across and between disciplines for postgraduate and early career researchers.

Competition details

The following project is one of eighteen being advertised as part of a competitive process for funding, there are a maximum of nine awards available.

Project Details

Two-dimensional (2D) van der Waals (vdW) materials feature exotic electrical, magnetic, optical, and structural properties, providing energy and area efficiencies far exceeding what is possible with conventional electronics. Of particular interests here is recently discovered 2D vdW semiconducting antiferromagnet CrSBr [1,2]. CrSBr emerges as an outstanding candidate for quantum application because it possesses spin-correlated excitons with strong anisotropy, exhibiting one of the largest exciton oscillator strengths in solids and high photoluminescence quantum yield. Furthermore, strong light-matter coupling has been recently demonstrated in this material, resulting in a previously unobserved class of quasiparticles with exciton-polaritons being coupled to magnons [1-3].

Recent theoretical calculations suggest that, in combination with other 2D layers such as graphene and transition metal dichalcogenides (TMDCs), CrSBr should allow for ultrafast control of electron spin [4]. TMDCs are of enormous interest because their local extrema in the electronic band structure called valleys are highly desirable for quantum computation with valley-based qubits. This project explores the design of metamaterials composed of TMDCs and 2D magnetic material CrSBr, with the ultimate goal of building a new generation quantum platform exploiting both valley and spin degree of freedom. Combining the properties of TMDCs and 2D magnets is extremely attractive for the quantum technologies because it consolidates the advantages of solid-state based qubits and photonic qubits. By proving the concept of novel, multi-functional qubits based on vdW materials, development of both quantum software and hardware is expected, which potentially could lead to commercial products and new applications in quantum technologies.

The project will primarily focus on time-resolved measurements using ultrafast laser pulses, to probe the dynamics of valleys and spins. I have recently demonstrated that similar heterostructures based on TMDCs and 2D magnets can lead to exotic phenomena such as all-optical switching via ultrafast charge transfer, and that such materials can be successfully probed in our laboratories in Exeter [5]. Thanks to unique coupling between excitons and magnons in CrSBr [1-3], dynamics of spins can be directly probed in time-resolved measurements, even though the spins form an antiferromagnetic order. Unlike other 2D magnets CrSBr is stable in air, substantially reducing the technological challenges associated with fabrication and making the proposed heterostructures particularly appealing to practical quantum applications. This project aligns with Quantum Technologies theme and if the proposed here approach based upon valley-spin states is to be recognized as the leading concept towards efficient quantum computing, it will have profound effect on the entire quantum industry.

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