Glossary¶

Instruments and signals¶

Term	Meaning in this portal
AFM	Atomic force microscopy: scanning a tip-sample interaction while a feedback loop controls a measured observable.
SPM	Scanning probe microscopy, the broader family that includes AFM and KPFM.
Cantilever	Microfabricated elastic beam carrying the tip; its modal stiffness is \(k\) (N m\(^{-1}\)).
Deflection sensitivity / InVOLS	Conversion from detector voltage to cantilever deflection, normally m V\(^{-1}\).
Feedback setpoint	Target observable maintained by the controller; its physical meaning depends on the operating mode.
Forward / backward scan	Opposite fast-axis scan directions. Their difference can reveal lag, drift, and feedback artifacts.
Optical lever	Laser, cantilever, and segmented photodiode arrangement used to infer cantilever angle or deflection.
Scanner	Piezoelectric positioning system moving the tip or sample along calibrated axes.
Topography	Reconstructed feedback height channel, not a direct photograph of an unconvolved surface.

Symbol or term	Definition and unit
\(F\)	Normal force, N.
\(d\)	Cantilever deflection, m.
\(\delta\)	Sample indentation under the chosen contact convention, m.
\(E\), \(E^*\)	Sample Young's modulus and reduced modulus, Pa.
\(\nu\)	Poisson ratio, dimensionless.
\(R\)	Spherical or paraboloidal tip radius, m.
\(\alpha\)	Conical tip half-angle, rad.
\(a\)	Contact radius in an adhesive-contact model, m.
\(w\)	Work of adhesion per area, J m\(^{-2}\).
Baseline	Non-contact reference fitted and subtracted before segmentation or fitting.
Contact point	Estimated transition defining the indentation origin; a fitted quantity with uncertainty, not an observed truth.
DMT	Derjaguin-Muller-Toporov adhesive-contact regime; SPM-Kit exposes a declared spherical-plus-offset approximation.
Hertz	Non-adhesive elastic contact model used here for a spherical/paraboloidal tip.
Hysteresis	Difference between compatible approach and retract paths; integrated force-distance area has units J.
JKR	Johnson-Kendall-Roberts adhesive-contact model; SPM-Kit's route is experimental.
Pull-off	Detachment event; the negative minimum after baseline correction is used as an operational adhesion magnitude.
Snap-in	Sudden transition toward the surface when the attractive gradient overcomes the cantilever response.
Sneddon	Axisymmetric indentation solution used here for ideal conical contact.

Symbol or term	Definition and unit
CPD, \(V_{\mathrm{CPD}}\)	Contact-potential difference, V; sign convention must be confirmed for the instrument.
\(\phi\)	Work function, normally eV in KPFM reporting.
KPFM	Kelvin probe force microscopy, an electrical-feedback SPM mode mapping a CPD-related observable.
\(S_a\)	Arithmetic mean absolute areal height deviation, same length unit as the height channel.
\(S_q\)	Root-mean-square areal height deviation, length.
\(S_z\)	Maximum areal height range under this implementation, length.
\(S_{sk}\), \(S_{ku}\)	Height-distribution skewness and kurtosis, dimensionless.
Leveling	Removing a declared reference form such as a plane or row offset. It changes reported statistics and low-frequency spectra.
Mask	Declared inclusion or exclusion set over a field. A mask changes the population being measured.
Pixel pitch	Lateral sample spacing, m pixel\(^{-1}\), derived from range and grid dimensions.

Symbol or term	Definition and unit
PSD	Power spectral density; normalization and dimensional convention must accompany comparisons.
\(q\)	Spatial frequency, m\(^{-1}\) under the cycles-per-length convention used here.
\(H\)	Hurst exponent of a declared self-affine fit, dimensionless.
\(D\)	Surface fractal dimension inferred here as \(3-H\), dimensionless and model-dependent.
\(\xi\)	Correlation length estimate, m, under a declared estimator and threshold.
\(f_0\)	Resonance frequency, Hz.
\(Q\)	Quality factor, \(f_0/\Delta f_{\mathrm{FWHM}}\), dimensionless.
\(m_{\mathrm{eff}}\)	Effective modal mass under a one-mode oscillator model, kg.
ASD	Amplitude spectral density, commonly m Hz\(^{-1/2}\) after calibration.
Thermal tuning	Estimating modal properties or stiffness from a calibrated thermal-noise spectrum.
d² law	Linear diameter-squared evaporation diagnostic, \(d^2=d_0^2-Kt\), under diffusion-limited assumptions.

Term	Meaning
Artifact contract	Declared file, schema, units, hashes, and provenance passed between tools.
Candidate dataset	Located material requiring licensing, suitability, integrity, and campaign review; not automatically accepted evidence.
Core	Presentation-independent SPM-Kit numerical and I/O package.
Fathom	Interactive workspace that invokes public SPM-Kit Core paths.
Level 1–5	Claim-scoped evidence vocabulary from software verification through independent reproducibility; see scientific status.
Phantom	Deterministic synthetic fixture with declared truth. It is not a physical reference.
Provenance	Source, version, parameters, units, transformations, environment, and checksums needed to inspect an artifact chain.
System under test	Installed public package or command invoked by a validation campaign without importing private internals.