Giant enhancement of exciton diffusion near an electronic Mott insulator

Data files

Aug 25, 2025 version files 369.40 MB

Files_2.zip

369.39 MB
README.md

2.70 KB

Abstract

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.

Dataset DOI: 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