Figure 1 : Image of the LaAlO3/SrTiO3 structure.

From: Clear leap for superconductors

Figure 1

A transparent (clear) gas of electrons is formed at the atomically abrupt interface between two oxide insulators — LaAlO3 and SrTiO3 — laid on top of each other. Caviglia et al.3 use an electric field to control the electron density at this interface and thereby study the emergence of superconductivity in the electron gas. (Image courtesy J. Mannhart.)