Novel electronically driven surface phase predicted in C/Si(111).
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.
Profeta
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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.
Tosatti
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E