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KPFM Data

KPFM-related data can be browsed and analysed inside the same SXM Viewer workspace as topography and other spectroscopy content - both as image channels and as bias-spectroscopy traces with dedicated fitting tools.

Where KPFM appears

Depending on the acquisition and import path, KPFM information may appear as:

  • image channels in the main preview or pop-outs
  • spectroscopy traces, analyzed with the same parabola-fit tooling as any other bias spectroscopy (see Parabola Fits) - the fit's headline output, the vertex of the fitted parabola, is labeled LCPD (local contact potential difference) throughout the app
  • associated data that can be exported or compared like other supported channels

The preview channel selector explicitly supports workflows where KPFM is one of several acquired channels.

Working with KPFM image channels

Treat KPFM image channels like other preview channels: switch to the channel in the preview or popup, adjust contrast and colormap locally, and use cropping, profiles, and export tools as needed.

LCPD vs. Z: the fit-trend dialog

For a stack of KPFM spectra taken at different tip heights, the fit-trend dialog ("Fit vs Z", available once a stack has fits with usable Z metadata) plots a chosen fit metric - LCPD, a, c, or RMSE - against Z/height across the whole stack, with:

  • Show errors - display propagated fit uncertainty as error bars
  • Relative Z - shift the Z axis so it starts at the fitted-Z minimum, instead of an absolute height
  • Sort by Z - order points by height rather than acquisition order

Its own Export CSV (Ctrl+E) saves the plotted metric-vs-Z table - see CSV & Data Export.

Matrix-wide fitting

For a KPFM matrix/grid dataset, Fit matrix parabolas... (see Matrix Scans) fits every pixel independently and produces seven 2D maps: a, LCPD, c, each of their fit errors, and RMSE - each with its own colormap and units. The dialog auto-detects which channel in the matrix is the Δf/KPFM channel to fit (scoring channel names containing "df"/"frequency"/"kpfm" and similar).

From there you can:

  • adjust the color scale mode (full range, clipped percentiles, or centered around zero)
  • hover a map to read its exact value at a point
  • Save maps... - writes the maps plus a JSON metadata sidecar
  • Export WSxM XYZ... - one XYZ file per parameter map

This turns a whole grid of individual bias sweeps into a spatial map of contact potential (and the other fit parameters) across the scanned area in one action.

A related tool converts a Δf(z) spectrum into a force-vs-distance curve (Sader-Jarvis method) using the cantilever's resonance frequency, spring constant, amplitude, and Q - see Parabola Fits.