Engineering topological states in atom-based semiconductor quantum dots

M Kiczynski; S K Gorman; H Geng; M B Donnelly; Y Chung; Y He; J G Keizer; M Y Simmons

doi:10.1038/s41586-022-04706-0

Engineering topological states in atom-based semiconductor quantum dots

Nature. 2022 Jun;606(7915):694-699. doi: 10.1038/s41586-022-04706-0. Epub 2022 Jun 22.

Authors

M Kiczynski^{1

2}, S K Gorman^{1

2}, H Geng^{1

2}, M B Donnelly^{1

2}, Y Chung^{1

2}, Y He^{1

3}, J G Keizer^{1

2}, M Y Simmons^{4

5}

Affiliations

¹ Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, UNSW Sydney, Kensington, New South Wales, Australia.
² Silicon Quantum Computing Pty Ltd, UNSW Sydney, Kensington, New South Wales, Australia.
³ Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China.
⁴ Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, UNSW Sydney, Kensington, New South Wales, Australia. michelle.simmons@unsw.edu.au.
⁵ Silicon Quantum Computing Pty Ltd, UNSW Sydney, Kensington, New South Wales, Australia. michelle.simmons@unsw.edu.au.

Abstract

The realization of controllable fermionic quantum systems via quantum simulation is instrumental for exploring many of the most intriguing effects in condensed-matter physics^1-3. Semiconductor quantum dots are particularly promising for quantum simulation as they can be engineered to achieve strong quantum correlations. However, although simulation of the Fermi-Hubbard model⁴ and Nagaoka ferromagnetism⁵ have been reported before, the simplest one-dimensional model of strongly correlated topological matter, the many-body Su-Schrieffer-Heeger (SSH) model^6-11, has so far remained elusive-mostly owing to the challenge of precisely engineering long-range interactions between electrons to reproduce the chosen Hamiltonian. Here we show that for precision-placed atoms in silicon with strong Coulomb confinement, we can engineer a minimum of six all-epitaxial in-plane gates to tune the energy levels across a linear array of ten quantum dots to realize both the trivial and the topological phases of the many-body SSH model. The strong on-site energies (about 25 millielectronvolts) and the ability to engineer gates with subnanometre precision in a unique staggered design allow us to tune the ratio between intercell and intracell electron transport to observe clear signatures of a topological phase with two conductance peaks at quarter-filling, compared with the ten conductance peaks of the trivial phase. The demonstration of the SSH model in a fermionic system isomorphic to qubits showcases our highly controllable quantum system and its usefulness for future simulations of strongly interacting electrons.

Publication types

Research Support, Non-U.S. Gov't