Engineering Quantum Criticality in the Integer Quantum Hall Regime

ORAL

Abstract

We investigate the influence of screened Coulomb interaction on the plateau-to-plateau transitions in the integer quantum Hall (IQH) regime using a GaAs double quantum well (QW) device. By tuning the carrier density in the top QW, we access both insulating and metallic screening phases of the top QW, allowing in-situ control of the electron-electron interaction strength in the bottom QW while keeping the disorder landscape fixed. In the unscreened regime, the temperature scaling exponent (κ) ranges from ≈ 0.32 to 0.49, consistent with the theoretical value κth ≈ 0.42 . When screening is introduced, κ is reduced to ≈ 0.23. We attribute this reduction to a change in the dynamical critical exponent (z) from z = 1 (long-range Coulomb interaction) to z = 2 (short-range screened interaction) [1,2]. These results provide direct experimental evidence for the role of electron-electron interaction in determining critical behavior in the IQH regime, and demonstrate screening as a powerful tuning parameter for engineering quantum criticality.

[1] D-H. Lee and Z. Wang, Phys. Rev. Lett. 76, 4014 (1996).

[2] P. Kumar, P. A. Nosov, and S. Raghu, Phys. Rev. Res. 4, 033146 (2022).

–

Presenters

  • Pranav Thekke Madathil

    • University of California, Berkeley

Authors

  • Pranav Thekke Madathil

    • University of California, Berkeley

  • Chia-Tse Tai

    • Princeton University

  • Adbhut Gupta

    • Princeton University

  • Loren N Pfeiffer

    • Princeton University

  • Krik W Baldwin

    • Princeton University

  • Mansour Shayegan

    • Princeton University