DOI: 10.5061/dryad.3r2280gv7
title: Giant enhancement of exciton diffusion near an electronic Mott insulator

description: Bose-Fermi mixtures naturally appear in various physical systems. In
 semiconductor heterostructures, such mixtures can be realized, with bosons
 as excitons and fermions as dopant charges. However, the complexity of
 these hybrid systems challenges the comprehension of the mechanisms that
 determine physical properties such as mobility. In this study, we
 investigate interlayer exciton diffusion in an H-stacked WSe2/WS2
 heterobilayer. Our measurements are performed in the dilute exciton
 density limit at low temperatures to examine how the presence of charges
 affects exciton mobility. Remarkably, for charge doping near the Mott
 insulator phase, we observe a giant enhancement of exciton diffusion of
 three orders of magnitude compared to charge neutrality. We attribute this
 observation to mobile valence holes, which experience a suppressed moire
 potential due to the electronic charge order in the conduction band, and
 recombine with any conduction electron in a non-monogamous manner. This
 new mechanism emerges for sufficiently large fillings in the vicinity of
 correlated generalized Wigner crystal and Mott insulating states. Our
 results demonstrate the potential to characterize correlated electron
 states through exciton diffusion and provide insights into the rich
 interplay of bosons and fermions in semiconductor heterostructures.
description: # Giant enhancement of exciton diffusion near an electronic Mott insulator
 Dataset DOI: [10.5061/dryad.3r2280gv7](10.5061/dryad.3r2280gv7) ##
 Description of the data and file structure The data here provides the gate
 voltage-dependent spatial diffusion of excitons measured through PL
 spectroscopy. The clear increase in diffusion around half-filling can be
 seen in these data sets. Lifetime and Spectrally resolved diffusion maps
 are also included for completeness. ### Files and variables #### File:
 Files_2.zip **Description:** The data files are sorted in different
 folders based on the figures they correspond to. Raw spatial PL intensity
 data files and Mathematica codes are included for easy access. 1.   In
 Fig1 folder, two data files for spectrally- and spatially-resolved PL
 intensity as a function of gate voltage are provided. The file with the
 name 5nW is for Fig. 1f. For Fig. 1e, the 80nW is the third set of the
 other file with multiple power datasets. The Mathematica code provided
 will directly plot the PL map depending on the file chosen. Fig. 2a and b
 in the manuscript can be extracted from the 5nW PL map dataset. 2.   In
 Fig2 folder, “Diff_spatial_5nW_0to5V_Rawplot_Fig2.txt” has the spatial map
 of PL diffusion for the entire electron doping range. The Mathematica file
 provided is for this datafile. The extracted 1D linecut and gaussian
 fitting datasets is also included. Lifetime vs gate-voltage dataset is
 also included in the folder. Diffusivity in Fig. 2d of manuscript is
 plotted by using both the diffusion length dataset and lifetime dataset.
 Additionally, two more datasets are included for spatial diffusion taken
 at two different spots. Also, two low power (1.5 nW and 5.7 nW) sets are
 provided. Mathematica code is provided for spot3 to directly plot and
 extract the diffusion length. 3.   For Fig4, Two separate data files are
 provided for Fig 4a covering the entire range of excitation powers
 measured ("110nWto2p3uW_21steps" means that 110 nW to 2.3 uW is
 the power range and 21 power steps of diffusion data sets are recorded in
 this range). Mathematica code is enclosed to plot and extract the
 diffusion length as a function of electron doping and excitation power.
 For temperature dependent diffusion (Fig 4b), separate data files (The
 file names indicate the temperature as 6K, 80K, 220K, and so on) are
 provided with their names indicating the temperature at which they are
 measured. 4.   For completeness of the raw datasets, we have also provided
 the files for spectrally resolved diffusion data along with the code. This
 dataset gives the plots in Fig. S7 of the manuscript. ## Code/software All
 codes are in Mathematica