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Towards tunable quantum criticality in InAs quantum wells: hybrid metal-semiconductor quantum dots for charge Kondo effects

ORAL

Abstract

Tunable quantum phase transitions based on the multichannel[1] and multi-island[2] charge Kondo effect has provided access to non-Fermi liquid quantum critical points. Work to date has been based on GaAs heterostructures, contacted by few-micron-size annealed metal islands. The large island size has limited studies to electron temperatures of 50 mK and below. The surface Fermi-level pinning in InAs affords direct ohmic contact to non-annealed sub-micron islands with large charging energies (Ec), offering the possibility of measurement over a 10x broader temperature range. We have demonstrated highly transparent interfaces (>99%) between quantum Hall edge states and sub-micron ohmic islands, and clean gate-defined constrictions in an InAs quantum well grown on InP. These building blocks enable the design of hybrid InAs/metal islands -- and arrays of effectively identical islands -- for simulating quantum criticality and gaining insight into Kondo lattice coherence.

  

[1] Iftikhar, Z. et al. Tunable quantum criticality and super-ballistic transport in a “charge” Kondo circuit. Science 360, 1315–1320 (2018).

[2] Pouse, W. et al. Exotic quantum critical point in a two-site charge Kondo circuit. arXiv:2108.12691 (2021).

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Publication: Hsueh, C.L., Sriram, P. et al. Clean quantum point contacts in an InAs quantum well grown on a lattice mismatched InP substrate. (in preparation)

Presenters

  • Praveen Sriram

    Stanford University

Authors

  • Praveen Sriram

    Stanford University

  • Connie L Hsueh

    Stanford University, Stanford Univ

  • Tiantian Wang

    Purdue University

  • Candice Thomas

    Purdue University, Purdue University, Microsoft Quantum Materials Lab-Purdue, West Lafayette, Indiana 47907, USA, CEA

  • Geoffrey C Gardner

    Purdue University, Purdue University, Microsoft Quantum Materials Lab-Purdue, West Lafayette, Indiana 47907, USA), Microsoft Quantum Materials Lab-Purdue

  • Marc A Kastner

    Stanford Univ, Stanford University

  • Michael J Manfra

    Department of Physics and Astronomy, Birck Nanotechnology Center, and Microsoft Quantum Lab Purdue, Purdue University, Purdue University, Purdue University, West Lafayette, Indiana 47907, USA

  • David Goldhaber-Gordon

    Stanford University, Stanford Univ