Quantum spin-Hall phase in van der Waals 2D systems for future quantum computation

Job type: 


Application deadline: 

Sunday, January 31, 2021

Reduction of electronic power consumption and elimination of losses, which cause the generation of parasitic heat, are key for reducing energy demands of digital processes and can be achieved through developing advanced functional materials and novel computational methodologies. This includes paradigms beyond traditional CMOS ‘von Neumann’ computing executing Boolean logic towards quantum computing and is underpinned by new materials. Topological quantum computing has been proposed as a method for overcoming the decoherence problem that plagues conventional qubits, but hardware implementations are as of yet non-existent. Quantum spin-Hall effect (QSHE) arises from the time-reversal invariant topological nature of matter where, in the 2D limit, the helical edge modes with opposite spin polarisation propagate at the boundary of the plane, whereas its bulk transport is prohibited. One of the novel and highly promising material systems that host QSHE in the truly 2D limit is a family of van der Waals quantum materials. One of them (WTe2) demonstrates the QSHE up to 100 K, which opens up a variety of research opportunities, due to the relative easiness and control of fabrication methods. This is in stark contrast to previous 2DEG MBE-grown systems where lattice matching is deadlocked, severely restricting a wide choice of heterostructures.

NPL and UCL have been collaborating on this 2D spin system and developed strong capability in terms of sample fabrication as well as advanced device characterisation. The aims of this studentship are to explore quantum-mechanical topological nature of QSHE in 2D quantum material heterostructures, such as by interfacing with ferromagnets and superconductors. UCL (Kurebayashi's group)recently acquired a 2D material fabrication system to fabricate a variety of heterostructures from 2D magnetic/topological materials. The fabricated devices will be characterised in UCL for GHz spin excitations and in NPL (Kazakova's group) for high magnetic field quantum transport experiments. A student on this project will fabricate novel 2D heterostructures, measure their transport and magnetic properties and analyse the results with strong supports offered by both research groups. The student will travel across the world to disseminate their latest research results and to interact with scientists in the research community. The project student will be able to interact with scientists from Hitachi Cambridge Laboratory that is an industrial partner of this joint project.

We are looking for highly motivated students with suitable undergraduate training in relevant subjects, including physics, engineering and materials science. Students who are interested in this project are encouraged to contact to Dr Cubukcu (NPL) and Dr Kurebayashi (UCL) for further details. A student on this project will join very successful CDT in the Advanced Characterisation of Materials, where a cohort of around 12 students starts on their PhDs together in the programme, taking our materials characteriation training and lectures in the first three months before starting their own research projects. Our CDT also has regular workshops where the whole cohorts get together and discuss their latest research achievements with social activities. More details are available from the link below.

UCL Kurebayashi's group: https://www.ucl.ac.uk/spintronics/

NPL Kazakova’s group: https://www.npl.co.uk/quantum-detection/low-loss-electronics


CDT in the Advanced Characterisation of Materials:


Dr Murat Cubukcu (NPL), murat.cubukcu@npl.co.uk, https://www.npl.co.uk/about-us/people/profiles/murat-cubukcu