Atomic-scale double-slit interferometer created with a focused electron beam in silicon
A focused electron probe placed between two silicon atomic columns generated double-slit interference fringes, revealing correlated thermal vibrations at the atomic level.
By positioning a sub-angstrom electron probe between adjacent silicon [110] atomic columns, scientists turned the crystal itself into an atomic-scale double-slit interferometer. Convergent-beam diffraction patterns recorded with 4D-STEM displayed clear interference fringes whose spacing matched the 1.36 Å column separation, and these fringes remained observable up to 900 K. Multislice simulations demonstrated that only a model incorporating correlated phonon displacements could replicate the high-order fringes, while an Einstein-type independent-vibration model failed.
Fitting the experimental data yielded correlation coefficients ρx and ρy, which directly relate to anisotropic bond stiffness and reveal the contribution of specific low-energy acoustic phonon modes to decoherence. This approach provides a real-space probe of vibrational correlations at the single-bond level, complementing existing bulk phonon measurement techniques. The method works across a range of specimen thicknesses and could be extended to arbitrary atomic pairs, opening pathways to study defects, interfaces and other non-periodic structures.
Why it matters
It provides a direct way to measure local atomic vibrations, key for designing materials with tailored thermal and mechanical properties.
In this story
