High Concentration Intrinsic Defects in MnSb₂Te₄.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• MnSb2Te4 shares structural similarities with the emerging material MnBi2Te4.
• Prior theoretical studies indicated negative formation energy for Mn antisite defects in MnSb2Te4, suggesting instability.
• Experimental synthesis of MnSb2Te4 contradicts theoretical predictions of instability.

Purpose of the Study:

• Investigate the growth environment and intrinsic defects in MnSb2Te4.
• Determine the stability and distribution of Mn antisite defects.
• Understand the impact of Mn antisite defects on magnetic properties.

Main Methods:

• First-principles calculations to investigate defect formation energies.
• Thermodynamic equilibrium calculations to determine defect concentrations.
• Analysis of defect distribution and impact on magnetic coupling.

Main Results:

• Mn antisite defect identified as the most stable intrinsic defect in MnSb2Te4.
• Mn-rich growth environments favor the formation of Mn antisite defects.
• Thermodynamic equilibrium concentrations of Mn antisite defects can reach up to 31% under Mn-rich conditions.
• Mn antisite defects promote a uniform distribution.
• Mn antisite defects induce a transition from antiferromagnetic to ferromagnetic coupling.

Conclusions:

• The Mn antisite defect is crucial for understanding MnSb2Te4 properties.
• Growth conditions significantly influence defect concentration and magnetic behavior.
• Controlled defect engineering offers a pathway to tune the magnetic properties of MnSb2Te4.