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Title: Negative-U centers as a basis of topological edge channels

We present the findings of the studies of the silicon sandwich nanostructure that represents the high mobility ultranarrow silicon quantum well of the p-type (Si-QW), 2 nm, confined by the δ-barriers, 3 nm, heavily doped with boron on the n-type Si (100) surface. The ESR studies show that nanostructured δ-barriers confining the Si-QW consist predominantly of the dipole negative-U centers of boron, which are caused by the reconstruction of the shallow boron acceptors along the <111> crystallographic axis, 2B{sup 0}→B{sup +}+B{sup −}. The electrically ordered chains of dipole negative-U centers of boron in the δ-barriers appear to give rise to the topological edge states separated vertically, because the value of the longitudinal, G{sub xx} = 4e{sup 2}/h, and transversal, G{sub xy} = e{sup 2}/h, conductance measured at extremely low drain-source current indicates the exhibition of the Quantum Spin Hall effect. Besides, the Aharonov-Casher conductance oscillations and the “0.7⋅(2e{sup 2}/h)-feature” obtained are evidence of the interplay of the spontaneous spin polarisation and the Rashba spin-orbit interaction that is attributable to the formation of the topological edge channels. We discuss the phenomenological model of the topological edge channel which can demonstrate the ballistic, Aharonov-Chasher effect or Josephson junction behaviour in dependence on the disorder in themore » distribution of the negative-U dipole centers in the upper and down d-barriers.« less
Authors:
; ; ; ;  [1] ;  [2] ;  [3]
  1. Ioffe Physical Technical Institute, Polytekhnicheskaya 26, 194021 St. Petersburg (Russian Federation)
  2. Technische Universitaet Berlin, D-10623, Berlin (Germany)
  3. St. Petersburg State Polytechnical University, Polytekhnicheskaya 29, 195251 St. Petersburg (Russian Federation)
Publication Date:
OSTI Identifier:
22263694
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1583; Journal Issue: 1; Conference: ICDS-2013: 27. international conference on defects in semiconductors, Bologna (Italy), 21-26 Jul 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BORON; DIPOLES; DOPED MATERIALS; ELECTRON SPIN RESONANCE; HALL EFFECT; JOSEPHSON JUNCTIONS; L-S COUPLING; OSCILLATIONS; POLARIZATION; QUANTUM WELLS; SILICON; SPIN