“Surface reconstruction” is when the surface energy is reduced by creating atomically flat surfaces which thus possess fewer dangling bonds.

Sure, let's break down the concept of "surface reconstruction" step by step:

1. Surface Energy: This is the energy associated with the surface of a material. Atoms at the surface are not surrounded by other atoms on all sides, which makes them less stable and increases the surface energy.

2. Dangling Bonds: These are unsatisfied bonds that occur at the surface of a material because the atoms at the surface do not have as many neighboring atoms to bond with compared to atoms in the bulk of the material.

3. Atomically Flat Surfaces: These are surfaces that are smooth at the atomic level, meaning there are fewer irregularities and steps on the surface.

4. Reduction of Surface Energy: The material tends to minimize its surface energy to become more stable. One way to achieve this is by rearranging the atoms on the surface.

5. Surface Reconstruction: This is the process where the atoms on the surface rearrange themselves to form a new structure that has lower surface energy. This often results in atomically flat surfaces with fewer dangling bonds.

In summary, surface reconstruction is a phenomenon where the surface atoms rearrange to form a more stable structure with reduced surface energy and fewer dangling bonds, leading to atomically flat surfaces.