Giant corrugations in Bi2Se3 layers grown on high-index InP substrates

Epitaxial growth of Bi2Se3 layers usually takes place in the (0001) orientation due to the stability of this surface terminated by the van der Waals bonds. Here, we show that the layers grown on InP(11n) substrates (n = 3, 4, and 5) are not (0001) oriented. The approximate lattice match at the heterointerface leads to an alignment between the [0001] direction of Bi2Se3 and the [111] direction of InP. The consequential tilt of the Bi2Se3(0001) plane with respect to the surface of the high-index substrates gives rise to a formation of giant corrugations consisting of the (0001) and (1 (1) over bar 00) facets. We demonstrate critical influences of the in-plane polarization and miscut of the substrates which emerge owing to the strong overlayer-substrate interaction in the semicoherent heteroepitaxy: Twin domains are eliminated and the layers are strained to the extent that the lattice symmetry is altered. We examine the Dirac band structure under strain using density functional calculations. The Dirac point shifts away from the Gamma point and the spin degeneracy is lifted when the strain is in the Bi2Se3[1 (1) over bar 00] direction as the spatial inversion symmetry is removed.