High Concentration Intrinsic Defects in MnSb(2)Te(4)

MnSb(2)Te(4) has a similar structure to an emerging material, MnBi(2)Te(4). According to earlier theoretical studies, the formation energy of Mn antisite defects in MnSb(2)Te(4) is negative, suggesting its inherent instability. This is clearly in contrast to the successful synthesis of experimental samples of MnSb(2)Te(4). Here, the growth environment of MnSb(2)Te(4) and the intrinsic defects are correspondingly investigated. We find that the Mn antisite defect is the most stable defect in the system, and a Mn-rich growth environment favors its formation. The thermodynamic equilibrium concentrations of the Mn antisite defects could be as high as 15% under Mn-poor conditions and 31% under Mn-rich conditions. It is also found that Mn antisite defects prefer a uniform distribution. In addition, the Mn antisite defects can modulate the interlayer magnetic coupling in MnSb(2)Te(4), leading to a transition from the ideal antiferromagnetic ground state to a ferromagnetic state. The ferromagnetic coupling effect can be further enhanced by controlling the defect concentration.