Intertwined electronic and structural phase transitions in the In/Si(111) interface

The structural (4x1) to (8x2) transition and the electronic metal to semimetal transition at the In/Si interface are studied with scanning tunneling microscopy and spectroscopy. Both transitions are gradual, resulting in a complex domain structure in the transition temperature regime. At these intermediate temperatures, the metallic (4x1) and semimetallic (8x2) domains coexist with each other and with new nanophases. By probing the two intertwined but distinguishable transitions at the atomic level, the interaction between different phases is visualized directly.