Jahn-Teller distortion in dangling-bond linear chains fabricated on a hydrogen-terminated Si(100)-2 x 1 surface

Length-dependent charge redistribution in dangling-bond (DB) linear chains fabricated on a hydrogen-terminated Si(100)-(2 x 1) surface is analyzed by using scanning tunneling microscopy and first-principles calculations. The second-layer Si atoms are displaced alternately to form pairs with charge redistribution, which is explained by the Jahn-Teller distortion in an artificial pseudomolecule. In a short even-numbered (DB) structure an unpaired second-layer Si atom exists and behaves as a soliton accompanied by the flip-flop motion of the structure. We point out that the odd-even problem, the edge effect, and the finite length of the DB structures are indispensable to understand the relaxation in the structures.