Data for Anomalous density fluctuations in a strange metal

This is the complete dataset for the "Anomalous density fluctuations in a strange metal" Proceedings of the National Academy of Sciences publication (https://doi.org/10.1073/pnas.1721495115). This is an integration of the Zenodo dataset which includes raw M-EELS data.

<b>METHODOLOGICAL INFORMATION</b>

1. Description of methods used for collection/generation of data: Data have been collected with a M-EELS instrument and according to the data acquisition protocol described in the original PNAS publication and in SciPost Phys. 3, 026 (2017) (doi: 10.21468/SciPostPhys.3.4.026)

2. Methods for processing the data: Raw data were collected with a channeltron-based M-EELS apparatus described in the reference PNAS publication and analyzed according to the procedure outlined both in the PNAS paper and in SciPost Phys. 3, 026 (2017) (doi: 10.21468/SciPostPhys.3.4.026). The raw M-EELS spectra at each momentum have been subject to minor data processing involving:
(a) averaging of different acquisitions at the same conditions,
(b) energy binning,
(c) division of an effective Coulomb matrix element (which yields a structure factor S(q,\omega)),
(d) antisymmetrization (which yields the imaginary chi)
All these procedures are described in the PNAS paper.

3. Instrument- or software-specific information needed to interpret the data: These data are simple .txt or .dat files which can be read with any standard data analysis software, notably Python notebooks, MatLab, Origin, IgorPro, and others. We do not include scripts in order to provide maximum flexibility.

4. Relationship between files, if important: We divided in different folders raw data, structure factors and imaginary chi.


<b>DATA-SPECIFIC INFORMATION</b>

There are 8 folders within the Data_public_deposition_v1.zip. Each folder contain data needed to create the corresponding figure in the publication.

<b>1. Fig1:</b> This folder contains 21 DAT files needed to plot the theory data in panels C and D, following this naming conventions:

[chiA]or[chiB]or[Pi]_q_number.dat

With chiA is the imaginary RPA charge susceptibility with a Coulomb interaction of electronically weakly coupled layers

chiB is the imaginary RPA charge susceptibility with the usual 4\pi e^2/q^2 Coulomb interaction.

Pi is the imaginary Lindhard polarizability.

q is momentum in reciprocal lattice units

Number is the numerical momentum value in reciprocal lattice units


<b>2. Fig2:</b> Files needed to plot Fig. 2 of the PNAS paper. Contains 3 folders as listed below. The files in this folder are named following this convention: Bi2212_295K_(1,-1)_50eV_161107_q_number_2.16_avg.dat,

295K is the sample temperature
(1,-1) is the momentum direction in reciprocal lattice units
50 eV is the incident e beam energy
161107 is the start date of the experiment in yymmdd format
Q is the momentum
Number is the momentum in reciprocal lattice units
2.16 is the energy range covered by the data in eV
Avg identifies averaged data

ImChi: is the imaginary susceptibility obtained by antisymmetryzing the structure factor

Raw_avg_data: raw averaged M-EELS spectra

Sqw: Structure factors derived from the M-EELS spectra

<b>3. Fig3:</b> Files needed to plot Fig. 3 of the PNAS paper. OP/ OD prefix identifies optimally doped or overdosed sample data, respectively.

ImChi: is the imaginary susceptibility obtained by antisymmetryzing the structure factor

Raw_avg_data: raw averaged M-EELS spectra

Sqw: Structure factors derived from the M-EELS spectra


<b>4. Fig4:</b> Files needed to plot Fig. 4 of the PNAS paper. The _fit_parameters.dat file contains the fit parameters extracted according to the fit procedure described in the manuscript and at all momenta.

ImChi: is the imaginary susceptibility obtained by antisymmetryzing the structure factor

Raw_avg_data: raw averaged M-EELS spectra

Sqw: Structure factors derived from the M-EELS spectra

<b>5. FigS1:</b> Files needed to plot Fig. S1 of the PNAS paper. There are 5 files in this folder. DAT files are M-EELS data following the prior naming convention, while the two .txt files are digitized data from N. Nücker, U. Eckern, J. Fink, and P. Müller, Long-Wavelength Collective Excitations of Charge Carriers in High-Tc Superconductors, Phys. Rev. B 44, 7155(R) (1991), and K. H. G. Schulte, The interplay of Spectroscopy and Correlated Materials, Ph.D. thesis, University of Groningen (2002).

<b>6. FigS2:</b> Files needed to plot Fig. S2 of the PNAS paper.

ImChi: is the imaginary susceptibility obtained by antisymmetryzing the structure factor

Raw_avg_data: raw averaged M-EELS spectra

Sqw: Structure factors derived from the M-EELS spectra


<b>7. FigS3:</b> Files needed to plot Fig. S3 of the PNAS paper. There are 2 files in this folder:

20K_phi_0_q_0.dat: is a M-EELS raw intensity at zero momentum transfer on Bi2212 at 20 K

295K_phi_0_q_0.dat: is a M-EELS raw intensity at zero momentum transfer on Bi2212 at 295 K

<b>8. FigS4:</b> Files needed to plot Fig. S4 of the PNAS paper. The _fit_parameters.dat file contains the fit parameters extracted according to the fit procedure described in the manuscript and at all momenta.

ImChi: is the imaginary susceptibility obtained by antisymmetryzing the structure factor

Raw_avg_data: raw averaged M-EELS spectra

Sqw: Structure factors derived from the M-EELS spectra