The development of ferromagnetism in Mn-doped Bi2Te3 is characterized through measurements on a series of single crystals with different Mn content. Scanning tunneling microscopy analysis shows that the Mn substitutes on the Bi sites, forming compounds of the type Bi2−xMnxTe3, and that the Mn substitutions are randomly distributed, not clustered. Mn doping first gives rise to local magnetic mom...

A hexagonal warping term has been proposed recently to explain the experimentally observed 2D equal energy contours of the surface states of the topological insulator Bi2Te3. Differing from the Dirac fermion Hamiltonian, the hexagonal warping term leads to the opening up of a band gap by an in-plane magnetization. We study the transmission between two Bi2Te3 segments subjected to different in-p...

This paper presents the process development towards a new generation of nanostructured thermoelectric generators for power harvesting from small temperature gradients by using a combination of traditional silicon microfabrication techniques, electroplating and submicron ion-track nanolithography. Polyimide nanotemplates with pore diameters ranging from 30 nm to 120 nm were fabricated. Prelimina...

Femtosecond pulses are used to excite A1g optical phonons in Bi2Te3, Sb2Te3, and Bi2Te3 /Sb2Te3 superlattice. Time-resolved reflectivity measurements show both the low-frequency and high-frequency components of A1g phonon modes. By comparing the phonon lifetime, it is found that the scattering rate inverse of lifetime in superlattice is significantly higher than those in Bi2Te3 and Sb2Te3. This...

The thermoelectric properties of Bi2Te3 nanowire/graphene composites prepared at different sintering temperatures have been investigated. The as-synthesized ultrathin Bi2Te3 nanowires are uniformly distributed between the graphene layers, leading to the formation of Bi2Te3 nanowire/graphene layer-by-layer hybrid structures. The electrical conductivity of the as-sintered composites increases dra...

The energy-filtering effect was successfully employed at the organic–inorganic semiconductor interface of poly(3-hexylthiophene) (P3HT) nanocomposites with the addition of Bi2Te3 nanowires, where lowenergy carriers were strongly scattered by the appropriately engineered potential barrier of the P3HT– Bi2Te3 interface. The resulting P3HT–Bi2Te3 nanocomposites exhibited a high power factor of 13....

Topological insulators are materials with a bulk band gap, but with topologically protected, spin polarized surface states with Dirac dispersion. Bi2Te3 is such a topological insulator with a single Dirac cone at the center of the Brillouin zone. ARPES studies have shown that the Fermi surface of Bi2Te3 changes from a circle to a hexagon, and then to a hexagram, when moving away from the Dirac ...

The optimization of the thermal co-evaporation deposition process for n-type bismuth telluride (Bi2Te3) thin films onto polyimide substrates for thermoelectric applications is reported. The influence of deposition parameters (evaporation rate and substrate temperature) on film composition and thermoelectric properties was studied for optimal thermoelectric performance. Energy-dispersive X-ray s...

Bi2Te3-based alloys have been intensively used for thermoelectric coolers and generators due to their high Seebeck coefficient S. So far, efforts to improve the S have been made mostly on changing the structures and components. Herein, we demonstrate an anomalous thermoelectricity in strained Bi2Te3 films, i.e., the value of S is obviously changed after reversing the direction of temperature gr...