Abstracts Book - IMRC 2018

• SF2-P058
BI-TE BASED TOPOLOGICAL INSULATORS COMPOUNDS BY
PHYSICAL VAPOR TRANSPORT
Omar Concepción 1 , Osvaldo de Melo 2 , Arturo Escobosa 3
1 Centro de Investigación y de Estudios Avanzados del IPN - CINVESTAV, Programa de
Doctorado en Nanociencias y Nanotecnología, Mexico. 2 Universidad de La Habana, Physics
Faculty, Cuba. 3 Centro de Investigación y de Estudios Avanzados del IPN - CINVESTAV, SEES,
Mexico.
For decades, Bi2Te3 has been studied as thermoelectric materials and recently as
topological insulator (TI). However, other Bi-Te phases exist which have received
much less attention. In fact, there have been reported at least seven different crystal
structures in the Bi-Te system but there are only a few reports on the preparation
of other phases different from Bi2Te3. The combination of Bi2Te3 and Bi bilayers,
which forms the different Bi-Te compounds, it should be expected that they will also
have a TI behavior.
This work presents a systematic study of the physical vapor transport (PVT) growth
of Bi-Te material focused in determining the adequate conditions for the
preparation of pure Bi2Te3 (tellurobismuthite), BiTe (tsumoite) or Bi4Te3 (pilsenite).
The samples were characterized by X-ray diffraction, Raman spectroscopy,
Rutherford backscattering spectroscopy and X-ray photoelectron spectroscopy.
The ability of the PVT technique to control the stability of different phases in the Bi-
Te system was demonstrated by optimizing the carrier gas flow and the substrate
temperature: for small flows, Te rich phases stabilize while by increasing the flow,
Bi richer phases are obtained. In vacuum this is not possible due to the transport
regime. The morphology between the pure Bi-Te phase samples was different. Hall
measurements showed that room temperature mobility decreases with increasing
Bi concentration.
Acknowledgment: The authors want to thank A. Tavira for XRD measurements,
M. Galván for Raman measurements, J. Roque for SEM images, D. Bahena for
AFM images, M. Manso for XPS measurements, V. Torres and A. Climent for
RBS measurements, MPI-CPfS and the financial support of CONACYT and the
program “Cátedras de Excelencia de la Comunidad de Madrid”.
Keywords: Topological insulator, Physical vapor transport, Bismuth telluride phases
Presenting authors email: ocdiaz89@gmail.com