Readme

This repository contains data associated with the publication "Dome-like pressure-temperature phase diagram of the cooperative Jahn--Teller distortion in NaNiO2".

Authors: -Liam A. V. Nagle-Cocco -James M. A. Steele -Shiyu Deng -Xiaotian Zhang -Dominik Daisenberger -Annalena R. Genreith-Schriever -Siddharth S. Saxena -Clare P. Grey -Sian E. Dutton

Contents

-The folder "experiment-logs" contains .xlsx files which list each pressure point and the preliminary pressures from the ruby fluorescence. Note that the preliminary pressures are not the same as those reported in the manuscript as they are not corrected for temperature. The two files are labelled as "first DAC" (which refers to the 294 K measurement) and "second DAC" (which refers to the 403 K measurement). -The folder "calibration-data" contains the gold and ruby pressure calibration details. It contains two subfolders: -"gold_V0_data" contains a measurement of the gold marker at ambient pressure and temperature, from which V0 is obtained to use in the Birch-Murnaghan fitting. The data is in the form of a 2D image, with the Dioptas file used for azimuthal integration. There is a Topas file which is the one used to Pawley refine the Au unit cell to obtain V0. -"lamb0_ruby" contains an ambient-pressure, ambient-temperature ruby fluorescence measurement used to obtain lambda_0. It also contains a Python script (in the form of a Jupyter notebook, .ipynb) used to fit the Voigts to the experimental spectrum. -There are two folders called "raw-experiment-data" followed by an underscore and the temperature of the measurement (294K or 403K). These folders contain the raw data from each DAC isothermal measurement. Within these folders are the following data: -"Ruby-files" contains the raw fluorescence spectra measured at each pressure/temperature point. -"first-DAC" or "second-DAC" contains the measured raw, non-azimuthally-integrated data used in this study. At some pressure/temperature points, multiple diffraction measurments were made at different spatial positions to account for changing position of the sample on compression; in these cases the best image was selected for azimuthal integration. -There is a folder called "integrated-diffraction-data" which lists all the 1D, integrated diffraction patterns used for sequential Pawley refinement.