Programmable Phase Selection between Altermagnetic and Noncentrosymmetric Polymorphs of MnTe on InP via Molecular...

Area of Science:

• Materials Science
• Solid State Physics
• Crystallography

Background:

• Selecting specific crystalline polymorphs during epitaxial growth is crucial for tuning material properties.
• Manganese telluride (MnTe) exhibits altermagnetic and noncentrosymmetric phases with potential for spintronics and microelectronics.

Purpose of the Study:

• To demonstrate programmable phase selectivity of MnTe polymorphs during molecular beam epitaxy (MBE) growth.
• To investigate the role of substrate surface termination and strain in controlling MnTe phase selection.

Main Methods:

• Epitaxial growth of MnTe on lattice-matched indium phosphide (InP) substrates with different surface terminations ((111)A and (111)B).
• Characterization using electron microscopy, X-ray photoemission spectroscopy (XPS), and reflection high-energy electron diffraction (RHEED).
• First-principles calculations to analyze interfacial energy and strain effects.

Main Results:

• The hexagonal NiAs-structure (altermagnetic MnTe) was stabilized on the In-terminated (111)A InP surface.
• The cubic ZnS-structure (noncentrosymmetric MnTe) was stabilized on the P-terminated (111)B InP surface.
• Phase selection was found to be initiated at the interface and propagate during growth.

Conclusions:

• Subtle modifications to the InP substrate surface enable precise control over MnTe polymorph selection during MBE.
• Interfacial termination and strain are key factors governing phase stabilization.
• High-quality, phase-pure MnTe films can be selectively grown, paving the way for novel spintronic and microelectronic applications.