John Wickham Steeds FRS FInstP[2] (born 9 February 1940) is a British physicist and materials scientist.
He has led a sophisticated research effort to make, from image plane diffraction analysis ("real-space crystallography") and convergent-beam diffraction, a complete system for crystallographic structure determination in the electron microscope.
[1][2] Significant applications include precipitate structure in steels, new phases in the contact regions of integrated circuits and the correction of important errors in the structure of transition metal dichalcogenides.
With the first observation of solitons (discommensurations) in the stripe and triply incommensurate states of these layer compounds, he has produced dynamic images of the basic phase-transition mechanisms.
[2][4] In 1996, he received the Holweck Medal, awarded jointly by the Institute of Physics and Société Française de Physique.