TY - JOUR
T1 - Stacking-dependent energetics and electronic structure of ultrathin polymorphic V2 VI3 topological insulator nanofilms
AU - Li, Can
AU - Winzer, Torben
AU - Walsh, Aron
AU - Yan, Binghai
AU - Stampfl, Catherine
AU - Soon, Aloysius
PY - 2014/8/29
Y1 - 2014/8/29
N2 - Topological insulators represent a paradigm shift in surface physics. The most extensively studied Bi2Se3-type topological insulators exhibit layered structures, wherein neighboring layers are weakly bonded by van der Waals interactions. Using first-principles density-functional theory calculations, we investigate the impact of the stacking sequence on the energetics and band structure properties of three polymorphs of Bi2Se3,Bi2Te3, and Sb2Te3. Considering their ultrathin films up to 6 nm as a function of its layer thickness, the overall dispersion of the band structure is found to be insensitive to the stacking sequence, while the band gap is highly sensitive, which may also affect the critical thickness for the onset of the topologically nontrivial phase. Our calculations are consistent with both experimental and theoretical results, where available. We further investigate tribological layer slippage, where we find a relatively low energy barrier between two of the considered structures. Both the stacking-dependent band gap and low slippage energy barriers suggest that polymorphic stacking modification may offer an alternative route for controlling the properties of this new state of matter.
AB - Topological insulators represent a paradigm shift in surface physics. The most extensively studied Bi2Se3-type topological insulators exhibit layered structures, wherein neighboring layers are weakly bonded by van der Waals interactions. Using first-principles density-functional theory calculations, we investigate the impact of the stacking sequence on the energetics and band structure properties of three polymorphs of Bi2Se3,Bi2Te3, and Sb2Te3. Considering their ultrathin films up to 6 nm as a function of its layer thickness, the overall dispersion of the band structure is found to be insensitive to the stacking sequence, while the band gap is highly sensitive, which may also affect the critical thickness for the onset of the topologically nontrivial phase. Our calculations are consistent with both experimental and theoretical results, where available. We further investigate tribological layer slippage, where we find a relatively low energy barrier between two of the considered structures. Both the stacking-dependent band gap and low slippage energy barriers suggest that polymorphic stacking modification may offer an alternative route for controlling the properties of this new state of matter.
UR - http://www.scopus.com/inward/record.url?scp=84908257539&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.90.075438
DO - 10.1103/PhysRevB.90.075438
M3 - Article
AN - SCOPUS:84908257539
SN - 1098-0121
VL - 90
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 7
M1 - 075438
ER -