Researchers turn cement into metal

Close-up visualizations of (A) the HOMO and (B) LUMO single-particle electron states in the 64CaO glass. Both states are spin-degenerate, and h1 labels the cavity (cage) occupied by LUMO. Yellow and magenta stand for different signs of the wave-function nodes. (C) Simulation box and the electron spin-density of the 64CaO glass with one oxygen subtracted at h2—that is, with two additional electrons. The two electrons have the same spin and they occupy separate cavities, h1 (boundary, also shown in B) and h2 (center, location of removed oxygen), which are separated by 12 Å from each other. (D) Cage structure around the spin-density of one electron cor- responding to the h2 cavity (close-up from C). Al, gray; Ca, green; O, red. Credit: ANL

I'll readily admit that the science behind this article, summarizing an article from the Proceedings of the National Academy of Sciences, is at the edge of my understanding of materials.

Apparently the scientists turned liquid cement into a semi-conductor analogous to liquid metal and eventually to a metallic-glass material, something that could lead to "positive attributes including better resistance to corrosion than traditional metal, less brittleness than traditional glass, conductivity, low energy loss in magnetic fields, and fluidity for ease of processing and molding."

The process seems to so obvious that I'm disappointed I didn't think of it myself:

The team of scientists studied mayenite, a component of alumina cement made of calcium and aluminum oxides. They melted it at temperatures of 2,000 degrees Celsius using an aerodynamic levitator with carbon dioxide laser beam heating. The material was processed in different atmospheres to control the way that oxygen bonds in the resulting glass. The levitator keeps the hot liquid from touching any container surfaces and forming crystals. This let the liquid cool into glassy state that can trap electrons in the way needed for electronic conduction

Seriously, though, can anybody explain this to me?

I can say that I know what the HOMO and LUMO shown in the diagram are. Those I remember from college chem.