First Principle Investigation of Electronic Structure,Magnetic Property and Valley Hall Conductivity Inmonolayer and Bilayermos2 Doped (Mn,V)
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Date
2018-02-02
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Addis Ababa University
Abstract
In the first and second parts of this dissertation structural stability, electronic structure
and magnetic interaction in transition metal(TM) atoms(V,Mn) doped monolayer
(ML) and bilayer(BL)MoS2 are studied within the density function theory(DFT)
based on DFT+U formalism. It is found that,the injection of V andMn atoms inMo
site of ML and BL MoS2 introduces magnetism and turns semiconductor behavior
of host MoS2 to half metallic nature. The magnetic interaction between dopants in
ML and BL MoS2 are always ferromagnetic irrespective of dopant configurations.
In contrast, in V doped case the magnetic interaction oscillates from ferromagnet
to antiferromagnet depending on the separation between dopants. Moreover,it is
found that interlayer interaction in doped BL MoS2 system affects not only electronic
structures but also the magnetic properties of the system. The calculated
ferromagnetic transition temperature (TC) inMn doped ML and BLMoS2 cases are
found to be above the room temperature (RT), whereas in V doped cases TC closer
to RT. In addition, TC increases with doping concentrations in a range of dilute limit
(6.5%) of magnetic atoms for doped ML and BL MoS2,which agrees with latest experimental
observed RT TC .Therefore based on our result, we suggest thatMn and
V doped ML and BL MoS2 are promising candidates for 2D DMS for high temperature
spintronics applications. In third part of this dissertation,using low energy
effective tight binding model together with consideration of dopant introduced exchange
field it is found that spin orbit coupling together with exchange energy determine
the valley polarization which in turn controls valley and spin Hall conductivity
in doped ML MoS2 system. Our results form another important step towards
information processing based on the valley degree of freedom.
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Keywords
Structural and Electronic Property, Valley Degree of Freedom InMoS, Plane Wave Approximation