Phases Control of Epitaxial MnTe through Buffer Layers
POSTER
Abstract
MnTe is one of the 3D semiconductors that can exhibit anomalous Hall effect. The potential edge states correlated with the alter-magnet properties especially in the α-phase MnTe is also under study these days. The epitaxial growth becomes one method to tune the electronic structure. In this work we have grown both α-phase and β-phase MnTe by Molecular Beam Epitaxy on GaAs (111) and sapphire (0001) substrates with different buffer layers.
While in bulk crystal MnTe α-phase is the most stable state at room temperature, in the epitaxial structure β-phase MnTe can also be achieved in the as-grown thin films without post-growth annealing. On GaAs (111) substrates α-phase MnTe are naturally favored without any buffer layer. When using Bi2Te3 series TI (topological insulators) the buffer layers on sapphire (0001) substrates, we found out that β-phase MnTe are favored on pure Bi2Se3 due to the smaller lattice mismatch. However, when we add some alloy effect to the buffer layer, though the lattice mismatch is still smaller in β-phase, α-phase is actually grown. This unveil the role of the entropy effect and the changed in the surface potential. The nanorods structure in MnTe α-phase can also be controlled by buffer layer control and a CrSex layer under it.
While in bulk crystal MnTe α-phase is the most stable state at room temperature, in the epitaxial structure β-phase MnTe can also be achieved in the as-grown thin films without post-growth annealing. On GaAs (111) substrates α-phase MnTe are naturally favored without any buffer layer. When using Bi2Te3 series TI (topological insulators) the buffer layers on sapphire (0001) substrates, we found out that β-phase MnTe are favored on pure Bi2Se3 due to the smaller lattice mismatch. However, when we add some alloy effect to the buffer layer, though the lattice mismatch is still smaller in β-phase, α-phase is actually grown. This unveil the role of the entropy effect and the changed in the surface potential. The nanorods structure in MnTe α-phase can also be controlled by buffer layer control and a CrSex layer under it.
Presenters
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Yuxing Ren
University of California, Los Angeles
Authors
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Yuxing Ren
University of California, Los Angeles
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Hanshen Huang
University of California, Los Angeles
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Lixuan Tai
University of California, Los Angeles
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Tao Qu
University of California, Los Angeles
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Kang L Wang
University of California, Los Angeles, Departments of Electrical and Computer Engineering, Physics and Astronomy, University of California, Los Angeles, California