Non-Abelian states at zero magnetic field in next-generation moiré MoTe2 heterostructures

Last year’s discovery of states hosting the fractional quantum Hall effect at zero magnetic field in a lattice system – zero-field fractional Chern insulators (FCIs) – has caused tremendous excitement within the condensed matter community.

These zero-field FCIs were first observed – by a team including the applicant – using both optics and transport in a molybdenum ditelluride (MoTe2) moiré superlattice. These states, analogs of the Jain sequence FQH states, host Abelian anyon excitations.

However, for certain twist angles, moiré MoTe2 is also predicted to host states with non-Abelian anyons - the main requirement for achieving scalable topologically protected quantum computation. These non-Abelian states have yet to be observed. Perhaps the largest difficulty in moiré systems is sample quality and twist angle control.

Contact resistance, strain, twist angle inhomogeneity, bubbles, and polymer residue can preclude the formation and observation of delicate non-Abelian FCIs.

The main goal of TOPOMAX is to investigate, using optical and transport measurements, the existence of non-Abelian states at zero magnetic field in ultra-high quality twisted MoTe2 heterostructures.

To achieve this, we will implement cutting-edge fabrication techniques that enable unprecedented twist angle control and homogeneity while allowing for devices compatible with optical and transport measurements.

In particular, the bent bilayer nanomanipulator technique will enable systematic investigation of zero-field FCIs as a continuous function of twist angle.

Determining whether the moiré MoTe2 system hosts non-Abelian states would lay the groundwork for study of zero-field non-Abelian anyons – and perhaps, one day, topologically protected qubits.