[Triumf-seminars] TRIUMF Colloquium today at 14:00

[TRIUMF Seminars]

Date/Time: Thu 2018-09-20 at 14:00

Location:  Auditorium          

Speaker:   Joshua Folk (UBC)

Title:     Nature's all-in-one: gateable superconductivity in the strongly correlated topological insulator WTe2

Abstract: The success of graphene research over the past decade has demonstrated the power of transistor-type measurements in 2D materials to investigate novel electronic states of matter.  In graphene, table-top electrical measurements routinely probe collections of interacting relativistic particles, under easily tuneable conditions such as density, temperature, and magnetic field.  Over the past ten years, the palette of elements and compounds available to construct 2D materials has been expanded well beyond carbon, and the range of condensed matter phenomena available to transistor-type measurements is consequently much wider.

Tungsten ditelluride, WTe2, is an example of a material that exfoliates like graphene, and can therefore form the building block of atomically-thin transistors. In a single material, WTe2 encompasses many of the most fascinating phenomena within condensed matter physics today.  Its heavy-metal constituents make WTe2 a quantum spin Hall insulator in monolayer form, as well as a semi-metal with overlapping electron and hole pockets.  We demonstrate that monolayer WTe2 is also a gate-tuneable superconductor when doped away from charge neutrality, and explore signatures of both strong correlations and the quantum spin Hall effect near the neutrality point.  With so many different electronic states available within one material, WTe2 offers a powerful platform for studying new physics, from Majorana fermions to excitonic insulators and beyond.




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