Negative-U centers as a basis of topological edge channels
- Ioffe Physical Technical Institute, Polytekhnicheskaya 26, 194021 St. Petersburg (Russian Federation)
- Technische Universitaet Berlin, D-10623, Berlin (Germany)
- St. Petersburg State Polytechnical University, Polytekhnicheskaya 29, 195251 St. Petersburg (Russian Federation)
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 the distribution of the negative-U dipole centers in the upper and down d-barriers.
- OSTI ID:
- 22263694
- Journal Information:
- AIP Conference Proceedings, Vol. 1583, 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); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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