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Quasi free-standing silicene in a superlattice with hexagonal boron nitride.

Kaloni TP, Tahir M, Schwingenschlögl U - Sci Rep (2013)

Bottom Line: In particular, the Dirac cone of silicene is preserved.Due to the wide band gap of hexagonal boron nitride, the superlattice realizes the characteristic physical phenomena of free-standing silicene.In particular, we address by model calculations the combined effect of the intrinsic spin-orbit coupling and an external electric field, which induces a transition from a semimetal to a topological insulator and further to a band insulator.

View Article: PubMed Central - PubMed

Affiliation: Physical Science & Engineering Division, KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia.

ABSTRACT
We study a superlattice of silicene and hexagonal boron nitride by first principles calculations and demonstrate that the interaction between the layers of the superlattice is very small. As a consequence, quasi free-standing silicene is realized in this superlattice. In particular, the Dirac cone of silicene is preserved. Due to the wide band gap of hexagonal boron nitride, the superlattice realizes the characteristic physical phenomena of free-standing silicene. In particular, we address by model calculations the combined effect of the intrinsic spin-orbit coupling and an external electric field, which induces a transition from a semimetal to a topological insulator and further to a band insulator.

No MeSH data available.


Superlattice of silicene (top) and hexagonal boron nitride (bottom) viewed along the hexagonal b-axis.
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f1: Superlattice of silicene (top) and hexagonal boron nitride (bottom) viewed along the hexagonal b-axis.

Mentions: The structural arrangement of the superlattice under study is depicted in Fig. 1, showing silicene and hexagonal boron nitride layers that alternate along the z-axis. We have also studied superlattices with hexagonal boron nitride slabs of varying thickness. However, since it turns out that this thickness has hardly any influence on the silicene electronic states, in particular the charge transfer between the two component materials, we will focus in the following on the case of one layer of hexagonal boron nitride alternating with one layer of silicene. Our structural optimization results in a Si–Si bond length of 2.26 Å and a buckling of 0.54 Å in the silicene layer. The latter value is slightly but not significantly higher than the predicted value of free-standing silicene616. The bond angle between neighboring Si atoms amounts to 114°, which agrees well with the value of 116° in free-standing silicene. For the interlayer distance between the silicene and hexagonal boron nitride layers we obtain a value of 3.35 Å, resembling the distance of a silicene layer from a h-BN substrate1011.


Quasi free-standing silicene in a superlattice with hexagonal boron nitride.

Kaloni TP, Tahir M, Schwingenschlögl U - Sci Rep (2013)

Superlattice of silicene (top) and hexagonal boron nitride (bottom) viewed along the hexagonal b-axis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824161&req=5

f1: Superlattice of silicene (top) and hexagonal boron nitride (bottom) viewed along the hexagonal b-axis.
Mentions: The structural arrangement of the superlattice under study is depicted in Fig. 1, showing silicene and hexagonal boron nitride layers that alternate along the z-axis. We have also studied superlattices with hexagonal boron nitride slabs of varying thickness. However, since it turns out that this thickness has hardly any influence on the silicene electronic states, in particular the charge transfer between the two component materials, we will focus in the following on the case of one layer of hexagonal boron nitride alternating with one layer of silicene. Our structural optimization results in a Si–Si bond length of 2.26 Å and a buckling of 0.54 Å in the silicene layer. The latter value is slightly but not significantly higher than the predicted value of free-standing silicene616. The bond angle between neighboring Si atoms amounts to 114°, which agrees well with the value of 116° in free-standing silicene. For the interlayer distance between the silicene and hexagonal boron nitride layers we obtain a value of 3.35 Å, resembling the distance of a silicene layer from a h-BN substrate1011.

Bottom Line: In particular, the Dirac cone of silicene is preserved.Due to the wide band gap of hexagonal boron nitride, the superlattice realizes the characteristic physical phenomena of free-standing silicene.In particular, we address by model calculations the combined effect of the intrinsic spin-orbit coupling and an external electric field, which induces a transition from a semimetal to a topological insulator and further to a band insulator.

View Article: PubMed Central - PubMed

Affiliation: Physical Science & Engineering Division, KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia.

ABSTRACT
We study a superlattice of silicene and hexagonal boron nitride by first principles calculations and demonstrate that the interaction between the layers of the superlattice is very small. As a consequence, quasi free-standing silicene is realized in this superlattice. In particular, the Dirac cone of silicene is preserved. Due to the wide band gap of hexagonal boron nitride, the superlattice realizes the characteristic physical phenomena of free-standing silicene. In particular, we address by model calculations the combined effect of the intrinsic spin-orbit coupling and an external electric field, which induces a transition from a semimetal to a topological insulator and further to a band insulator.

No MeSH data available.