Magnetic response induced by charge doping in two-dimensional magnetic Cr2TiC2O2 MXene

Abstract

Charge doping in two-dimensional materials, particularly in Cr-based MXene, a high spin-polarized material, induces magnetic responses that have significant potential for spintronic device applications. The practical application of these response mechanisms in this field is contingent upon their comprehension. In this study, first-principles calculations are implemented to investigate the influence of charge doping on the magnetic properties of Cr2TiC2O2. Cr2TiC2O2 prefers a ferromagnetic arrangement in its undoped state. When the electron loss per unit cell is below 0.8, a ferromagnetic-to-antiferromagnetic phase transition occurs and leads to an antiferromagnetic structure. Additionally, the easy magnetization axis switches from [001] to [100]. In addition to elevating the magnetic ordering temperature, electron loss also improves the exchange interaction (J1). Specifically, when the system loses 1.0 electron per unit cell, J1 increases from 4.19 to 9.73 meV, and the ordering temperature rises from 69 to 146 K. Charge transfer and partial density of states analysis are employed to reveal the fundamental mechanisms responsible for the magnetic phase transition and elevated magnetic ordering temperature. The prevalent surface effects of Cr2TiC2O2 make it a promising candidate for applications in magnetic sensing, surface adsorbate detection, and signal control.