"Graphene-Like" Exfoliation of Atomically-Thin Films of Bi₂Te₃ and Related Materials: Applications in Thermoelectrics and Topological Insulators

Abstract

We report on "graphene-like" exfoliation of the large-area crystalline films and ribbons of bismuth telluride with the thicknesses of a few atoms. It is demonstrated that Bi 2 Te 3 crystal can be mechanically separated into its building blocks -Te-Bi-Te-Bi-Te atomic five-foldswith the thickness of ~1 nm and even furtherto subunits with smaller thicknesses. The atomically-thin films can be structured into suspended crystalline ribbons providing quantum confinement in two dimensions. The quasi two-dimensional crystals of bismuth telluride revealed high electrical conductivity. The proposed atomic-layer engineering of bismuth telluride opens up a principally new route for drastic enhancement of the thermoelectric figure of merit.

Fermi-crossing Type-II Dirac fermions and topological surface states in NiTe2

“…Symmetry wise, the p -bands associated with B and AB levels at Γ and A points transform as the IREPs of the double space groups ( ), 19 , 20 . Because of the phase introduced, the B-AB splitting of the p z -states decreases from the Γ to the A point 13 . This induces strong k z dispersion and a large bandwidth for p z -derived bands as compared to planar p x,y orbitals.…”

“…Given that TMDs are being increasingly incorporated into device structures [12][13][14][15][16][17] , it is highly desirable to identify a candidate material whose transport properties might be predominantly derived from topologically protected states. An intriguing candidate in this regard is NiTe 2 .…”

The Property, Preparation and Application of Topological Insulators: A Review

“…TI is a general concern of science because its discovery is of great value to basic physics research and many semiconductor devices [ 4 ]. TI is another significant discovery after graphene, which will inevitably lead to the upsurge of research in the scientific community [ 5 ].…”