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Evidence for Symmetry Breaking in the Ground State of the Si(111)‐7 × 7: The Origin of Its Metal–Insulator Transition
Author(s) -
Demuth J. E.
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202070045
Subject(s) - condensed matter physics , ground state , symmetry (geometry) , metal–insulator transition , jahn–teller effect , symmetry breaking , charge (physics) , materials science , physics , metal , quantum mechanics , geometry , mathematics , metallurgy , ion
The perspective and top view of an ideal room‐temperature unit cell of a new 5×5 honeycomb structure on Si(111), called the InterDigitated‐Faulted‐Adatom model (or DFA), are displayed on the frontispiece page. This 5×5 transforms at higher temperatures into a similar 7×7 DFA that is discussed by J. E. Demuth in article number 2000229 . The 7×7 exhibits many paradoxical properties unaccounted for within current effective one‐electron calculations. Evidence is presented for a Jahn–Teller distortion in its ground state and phonon‐assisted adatom charge density distortions with increasing temperature. The symmetry properties of this new class of structures and the formation of resonance surface states are shown to account for this unusual behavior.