title: Novel electronically driven surface phase predicted in C/Si(111).
abstract: We predict a novel electronically driven phase for the recently created C/Si(111) surface at 1/3 monolayer coverage. Whereas the isoelectronic surface Sn/Ge(111) is a 3 x 3 distorted metal and Si/SiC(0001) is an undistorted magnetic Mott insulator, the new phase combines both features. Two of three adatoms in C/Si(111) should form a distorted (3 x 3) honeycomb sublattice, the third an undistorted insulating and magnetic triangular sublattice. The generally conflicting elements, namely, band energy, favoring distortion, and strong electron correlations favoring a Mott state, actually conspire in this case. This kind of state represents the surface analog of the Fazekas-Tosatti state in the charge density wave compound 1T-TaS2.
authors.affiliation: C.A.S.T.I.-Istituto Nazionale Fisica della Materia and Dipartimento di Fisica, Università degli studi dell'Aquila, I-67010 Coppito (L'Aquila), Italy.
authors.forename: G
authors.initials: G
authors.lastname: Profeta
authors.forename: E
authors.initials: E
authors.lastname: Tosatti