Semimetallic Hall properties of PbTe-SnTe superlattice

Abstract

The PbTe-SnTe superlattice was expected to be a type-II superlattice where the valence band edge of SnTe is higher than the conduction band edge of PbTe. To ascertain the type-II structure, we prepared the PbTe-SnTe superlattice by hot wall epitaxy, and performed its Hall measurement. Magnetic-field-dependent and relatively small Hall coefficients were obtained for the superlattices, which show coexistence of free electrons and holes in the superlattice. Hall coefficients of the superlattices increased with annealing time owing to the gradual disappearance of the coexistence. Diffusion of Sn was studied using x-ray diffraction analysis.

Density functional study of graphene overlayers on SiC

“…We find that albeit small, the LSDA relaxation is associated with a sizable energy gain of 0.097 eV. Our LDA results are in good agreement with the LDA results of Sabisch et al [57], who found a relaxation of 12 z D of 24% with an energy gain of 0.09 eV.…”

“…As the carbon layer is, in fact, more rigid than the SiC crystal, the elastic stress should propagate z z 12 …”

“…The inverted-band structures can be realized, as proposed in [8], with the ternary semiconductors such as Pb 1 x -Sn x Te or Hg 1 x -Cd x Te. The energy gap in these materials changes sign as a function of the composition x. Experimentally, the band-inverted superlattices of alternating CdTe and HgTe layers as well as of the PbTe and SnTe layers (these binary semiconductors have opposite signs of g ε ) have been grown [11,12] and unusually high in-plane electron mobilities have been reported [13]. Yet it is difficult to single out the interface contribution in such superlattices and the suggestion largely remained an academic example of a potentially realizable Weyl electron system.…”

IV-VI Narrow-Gap Superlattices

“…In such case one can expect the electrons from valence band of SnTe to flow the conduction band of PbTe, leading to a semimetallic stucture. The magnetic field and temperature dependences of the Hall coefficient RH(H, T) of PbTe/SnTe SL grown both on BaF2 [32] and KCl [33] substrates do show a large variations characteristic for the presence of two types of carriers. Moreover the investigations of RH(H) at Τ = 5 K show that RH(H) changes its sign from the negative to positive [33], strongly indicating that electrons with higher mobilities (in PbTe layers) and holes with lower mobilities (in SnTe layers) coexist in the structure.…”

Green Function Approach to Interface States in Band‐Invert ed Junctions

“…In a band-inverted heterojunction the fundamental gap, defined as the difference between Γ 6 and Γ 8 energies, has opposite signs on each side [1]. Type III superlattices with band inversion of CdTe/HgTe and PbTe/SnTe has been successfully grown in the past [2,3]. One of the most conspicuous characteristic of bandinverted heterojunctions is the existence of interface states lying within the fundamental gap, provided that the two gaps overlap [4][5][6][7][8].…”