Strongly correlated metals — a family including currently hot systems such as high temperature superconducting cuprates and colossal magnetoresistive manganites — have so far been known for their "bulk" properties: a sample of these materials is superconducting or magneto-resistive as a whole, with real and potential applications in various areas of science and technology.

In theoretical work recently highlighted in Physical Review Letters, Giovanni Borghi, Michele Fabrizio and Erio Tosatti showed that metallicity must dwindle near the sample surfaces, giving rise to a "dead layer" — a feature whose existence and properties are supported by a companion synchrotron spectroscopy experiment. The presence of the dead layer should be of importance for numerous measurements and applications of these materials that involve surfaces or interfaces.

The article, titled "Surface Dead Layer for Quasiparticles Near a Mott Transition", appeared in the 11 February edition of Physical Review Letters.