Surface States, Surface Metal-Insulator, and Surface Insulator-Metal Transitions

摘要

I present an informal discussion of various cases where two-dimensionalsurface metal-insulator structural and charge-density-wave instabilities drivenby partly filled surface states have been advocated. These includereconstructions of clean semiconductor surfaces and of W(100) and Mo(100), aswell as anomalies on the hydrogen-covered surfaces H/W(110) and H/Mo(110), andpossibly alkali-covered surfaces such as K/Cu(111). In addition I will alsodiscuss the opposite type of phenomena, namely surface insulator-metaltransitions, which can be argued to occur on $\alpha -$% Ga(001),high-temperature Ge(111), and probably Be(0001).