Photon echo in the Coloumb glass phase as observed with 2D non-linear THz spectroscopy

ORAL

Abstract

Phosphorous doped Silicon (P:Si) near the metal insulator transition (MIT) hosts a Coulomb glass phase where charge carriers are localized and have strong long-range Coulomb interactions. Here we perform 2D non-linear THz spectroscopy to study the low energy non-linear electrodynamics of charge carriers in the Coulomb phase. Two time-delayed THz pulses with field strengths on the order of 100 kV/cm are applied sequentially on the sample to extract a 2D spectrum of the non-linear susceptibility of the sample as a function of emission and absorption frequencies. Distinct third-order nonlinear signals are identified in the 2D spectra including a photon echo, the anti-diagonal linewidth of which is used to determine the decoherence time (T2) of excited carriers. This is compared with the energy relaxation time (T1) to understand the interplay between site disorder and long-range interactions as the MIT is approached.

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Presenters

  • Fahad Mahmood

    University of Illinois at Urbana-Champaign

Authors

  • Fahad Mahmood

    University of Illinois at Urbana-Champaign

  • Dipanjan Chaudhuri

    Johns Hopkins University

  • David Barbalas

    Johns Hopkins University

  • Rahul Nandkishore

    Physics, University of Colorado, Boulder, University of Colorado, Boulder, Department of Physics, University of Colorado, Boulder, University of Colorado Boulder

  • Peter Armitage

    Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, Johns Hopkins University, Institute of Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University