International Journal of Advancements in Technology
Open Access

Topological insulators based on the semi-metallic HgCdTe alloys

Joint Event on Frontiers in Materials Science Engineering and Nanotechnology

May 13, 2019 Brussels, Belgium

E. M. Sheregii, Michal Marchewka, Dariusz Zak and Pawel Sliz

University of Rzeszow, Poland

Scientific Tracks Abstracts: Int J Adv Technol

Abstract :

Experimental results of the magneto-transport measurements over a wide interval of temperatures for nineteen layers of MCT (x ≈ 0.13 - 0.15) grown by MBE are presented in this report. The results obtained for sample A9 – strained thin layer on the GaAs/CdTe substrate – are presented. The Rxx(B) and Rxy(B) curves are shown for different temperatures over wide range from 0.4K to 50K. The well-defined quantized plateaus in Rxy with values h/(2e2) = 12.9 kΩ, accompanied by vanishing Rxx is observed at 0.4K what explicitly indicate on the Integer Quantum Hall Effect (IQHE) and Shubnikov-de Haas (SdH) oscillations characteristic for 2D electron gas. The Rxx(B) and Rxy(B) curves are reproducible up to 20K and above this temperature the Integer Quantum Hall Conductivity (IQHC) is observed up to 50K. That can be explained by conductivity on topologically protected surface states (TPSS). An amazing temperature stability of the SdH-oscillation period and amplitude is observed in the entire temperature interval of measurements up to 50K. Moreover, the IQHE behavior of the Hall resistance is registered in the same temperature interval. In the case of not strained layers it is assumed that the QHC on the TPSS contributes also to the conductance of the bulk samples. As Topological Insulator (IT) HgCdTe have important advantages: high value of the Fermi velocity – approximately the same as for graphene, what leads to an increase in the attractiveness of this TI for future applications: as Weyl phase. In comparison with pure HgTe: the energy dispersion in semimetal HgCdTe is closer to linearity in the wider range of the momentum what lead to an increase in the attractiveness of the TI based on semimetal HgCdTe alloy for future applications: as massless Weyl fermions for example with addition of non-compensated spins of Mn.

Biography :

Eugen M. Sheregii (in pass: Eugeniusz Szeregij), Education: Uzhgorod University (1971); A. F. Joffe Physical-Technical Institute in Leningrad – PhD (1976); St. Petersburg University of Technology – Doctor of Science (1992); Employment: University of Rzeszow – Full Professor (1999 – now). Activities: The cyclotron-phonon resonance with absorption of two acoustic phonons (1987); the magneto-phonon resonance with simultaneous emission and absorption of two phonons belonging to different sublattices of the semiconductor solid solution was discovered in 1988. Discontinuity of the phonon frequencies temperature dependence caused by the Dirac point in HgCdTe (2009); SERS based on nano-complexes Au+Oxidise enzyme (2015); Topological Insulators based on HgCdTe (2017). Honours and memberships: Member of E-MRS Board, Polish Physical Society – Member (1994), Awards: Awards of Rector for Scientific works (2002, 2009), Award of Ministry of Science and Higher Education – 2014.

E-mail: sheregii@ur.edu.pl