The full dataset is reported in the following files, including magnetoresistance curves not included in the analysis described in the paper. Only the magnetoresistance traces showing clear beatings are used for the fitting procedure probing the larger density range possible. 

- sampleX_YmK_FFT_and_fit contain the full experimental dataset, from which the FFT and fittings described in the paper come from, where X corresponds to the device A - G, Y corresponds to the temperature 1.7K and 65mK
 data_Bfield_rhoxx_Rxy is a cell array containing experimental magnetic field [T], rhoxx [Ohm/sq.] and Rxy [Ohm] (when available) in column 1, 2, and 3, respectively. Increasing accumulation gate values are reported from the first cell to the last one
 delta_rho_for_FFT is a cell array containing 1/B [T^-1] and delta rhoxx [Ohm/sq.] used for FFT analysis, in column 1 and 2, respectively
 delta_rho_noBackground is a cell array containing 1/B [T^-1] and delta_rhoxx [Ohm/sq.] after background subtraction, in column 1 and 2, respectively
 FFT_f_density_Spectra_normSpectra is a cell array containing FFT results. frequency (f), density [cm^-2], FFT spectra [a.u.], and normalized spectra [a.u.], in column 1 to 4, respectively
 fit_xy is a cell array containing 1/B [T^-1] and normalized delta rhoxx [Ohm/sq.] from the fitting procedure, in column 1 and 2, respectively
 density_FFT_tot [cm^-2] is the total density extrapolated from FFT
 density_FFT [cm^-2] is the single valley population 1/2 extrapolated from FFT, in column 1 and 2, respectively
 density_delta_FFT [cm^-2] is the extrapolated valley density difference extrapolated from FFT
 fit_A and fit_A_err are the amplitude fitting parameter and relative 2sigma error from the fitting procedure
 fit_n1, fit_n1_err, fit_n2, and fit_n2_err [cm^-2] are the valley density 1 and 2 with relative 2sigma errors from the fitting procedure  
 fit_ntot [cm^-2] is the resultant total density from the fitting procedure
 fit_deltan [cm^-2] is the valleys density difference fitting parameter
 fit_tauQ and fit_tauQ_err [s] are the single particle relaxation time and relative 2sigma error from the fitting procedure
 fit_temp [K] is the temperature used for each device
 fit_VS [eV] is the valley splitting extrapolated from the fitting procedure
 frequency_peaks and frequency_delta_peaks are the FFT peaks frequency and their difference, respectively
 Vg [V] is the accumulation gate
 rho0 and rho0_lowfield [Ohm/sq.] are the longitudinal magnetoresistance at zero-field and at low-field, respectively 
 