Exploring Bonding Configurations in MnBi₂Te₄-Type Materials.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Monolayer MnBi2Te4 is a promising van der Waals (vdW) material with unique magnetic and topological properties.
• Understanding structure-property relationships is crucial for designing advanced vdW materials.

Purpose of the Study:

• To systematically investigate crystal structures of the form MnBX2X2, based on monolayer MnBi2Te4.
• To explore how tuning bonding configurations affects magnetic, electronic, and topological characteristics.
• To identify novel vdW materials with potential for quantum anomalous Hall effect (QAHE).

Main Methods:

• First-principles calculations were employed to analyze various crystal structures.
• Energetically favorable bonding configurations were determined.
• Magnetic exchange parameters and magnetic anisotropy energy were computed.

Main Results:

• The Mn-X bond length dictates the most stable bonding configuration in MnBX2X2 monolayers.
• Elements at the X sites primarily influence the magnetic properties.
• A stable phase of monolayer MnBi2S2Te2 (γ-MnBi2S2Te2) was predicted, exhibiting the quantum anomalous Hall effect (QAHE).

Conclusions:

• Bonding configuration is a key factor for tuning magnetic, electronic, and topological properties in MnBi2Te4-type vdW materials.
• The predicted γ-MnBi2S2Te2 offers a new platform for exploring QAHE.
• This research provides a pathway for designing functional vdW heterostructures.