Correlation-Driven Topological Transition in Janus Two-Dimensional Vanadates

Abstract

The appearance of intrinsic ferromagnetism in 2D materials opens the possibility of investigating the interplay between magnetism and topology. The magnetic anisotropy energy (MAE) describing the easy axis for magnetization in a particular direction is an important yardstick for nanoscale applications. Here, the first-principles approach is used to investigate the electronic band structures, the strain dependence of MAE in pristine VSi2Z4 (Z = P, As) and its Janus phase VSiGeP2As2 and the evolution of the topology as a function of the Coulomb interaction. In the Janus phase the compound presents a breaking of the mirror symmetry, which is equivalent to having an electric field, and the system can be piezoelectric. It is revealed that all three monolayers exhibit ferromagnetic ground state ordering, which is robust even under biaxial strains. A large value of coupling J is obtained, and this, together with the magnetocrystalline anisotropy, will produce a large critical temperature. We found an out-of-plane (in-plane) magnetization for VSi2P4 (VSi2As4), and an in-plane magnetization for VSiGeP2As2. Furthermore, we observed a correlation-driven topological transition in the Janus VSiGeP2As2. Our analysis of these emerging pristine and Janus-phased magnetic semiconductors opens prospects for studying the interplay between magnetism and topology in two-dimensional materials.

Theoretical predicted Janus SrAlGaTe4: effects of strain and electric field and its topological properties

“…Constructing stack structures (for example, van der Waals heterojunction [19,20]) or generating unsymmetrical structure (for example, Janus structures [21][22][23]), applying external strain [24] or electric field [25], and other methods, have been demonstrated significant modulation ability in the physical properties of 2D materials. For example, the correlation-driven topological transition can be observed in the Janus phase structure of the VSiGeP 2 As 2 [26]. The Rashba spin splitting and high electron carrier mobility have been investigated in Janus 2D materials MSiGeN 4 (M = Mo and W).…”

First-Principles Study Reveals an Electronic Correlation Effect on the Topological and Electronic Properties of Janus RuClF Monolayers: Implications for Spintronics and Valleytronics Applications

“…The concept of quasi-half-valley metal (QHVM) is proposed, which has attracted wide attention from researchers. For the sake of exploring novel applications and phenomena, − investigating various phase transitions play a crucial part in enriching our comprehension of different physical properties and emerging quantum states. In other words, diverse quantum states and interesting physical properties can be resulted by the phase transitions.…”

Manipulation of Valley and Spin Properties in Two-Dimensional Janus WSiGeZ4 (Z = N, P, As) through Symmetry Control

“…Subsequently, several predictions of these Janus 2D materials and their excellent physical properties have been carried out. This includes the quantum spin Hall state in SrAlGaTe 4 , high electron mobility, efficient photocatalysis, Rashba spin splitting, out-of-plane piezoelectricity in the MoSiGeN 4 , − and intrinsic ferromagnetism in the VSiGeN 4 . , Therefore, this class of materials is expected to provide intriguing physical phenomena, particularly in valleytronics and spintronics.…”