  Atom probe tomography is often introduced as providing "atomic-scale" mapping
of the composition of materials and as such is often exploited to analyse
atomic neighbourhoods within a material. Yet quantifying the actual spatial
performance of the technique in a general case remains challenging, as they
depend on the material system being investigated as well as on the specimen's
geometry. Here, by using comparisons with field-ion microscopy experiments and
field-ion imaging and field evaporation simulations, we provide the basis for a
critical reflection on how the spatial performance of atom probe tomography in
the analysis of pure metals, low alloyed systems and concentrated solid
solutions (i.e. akin to high-entropy alloys). The spatial resolution imposes
strong limitations on the possible interpretation of measured atomic
neighbourhoods, and directional neighbourhood analyses restricted to the depth
are expected to be more robust. We hope this work gets the community to reflect
on its practices, in the same way it got us to reflect on our own work.
