Strain‐Valley Coupling in 2D Antiferromagnetic Lattice

Abstract

In recent years, 2D valley physics has attracted tremendous attention in both fundamental research and device applications. The search for a coupling valley with exotic physical properties can enable the exploration of novel quantum devices and is therefore of significant interest. Here, using model analysis, a novel mechanism is proposed that realizes strong coupling between strain and valley physics in a 2D antiferromagnetic honeycomb lattice in a controllable fashion. This idea is to modulate the exchange interactions through strain, thereby mediating the inversion and time‐reversal symmetries. As valley physics are connected with the symmetries, this enables a strong strain‐valley coupling. On the basis of first‐principles calculations, the validity of this mechanism is further demonstrated in a series of single‐layer systems, i.e., AuCl3, CrI3, and VPTe3, which are predicted to host valley polarization and anomalous valley Hall effect. The change in bonding angle is found to play a crucial role in mediating the exchange interaction and thus the strain‐valley coupling process. The microscopic origin is also discussed. These explored phenomena and insights greatly enrich the valley physics and 2D materials research.

Valleytronics in two-dimensional magnetic materials

“…The field of research and the applications related to the utilization of valley degrees of freedom for storing and transmitting information is called valleytronics [10][11][12][13][14][15][16][17]. Valleytronics utilizes the valley quantum degree of freedom in combination with other degrees of freedom, such as charge and spin of electrons to encode information, providing a richer, more stable and efficient solution for information processing [18,19]. Valleytronics provides new opportunities for the development of next-generation electronic devices.…”

Magnetic and Ferroelectric Manipulation of Valley Physics in Janus Piezoelectric Materials

“…8−15 Generally, due to the inherent magnetic exchange interaction and spatial inversion symmetry breaking, the valley polarization (VP) is spontaneously introduced in 2D ferromagnetic systems after considering spin−orbit coupling (SOC). 16,17 Valley polarization is prone to occur in several 2D single-layer materials, such as the magnetic VSe 2 , 16 VSSe, 18 AuCl 3 , 19 CeI 2 , 20 RuCl 2 , 21 RuClX (X = F, Br), 22 VSi 2 P 4 23,24 and VGe 2 P 4 monolayers. 25 It is noteworthy that there is very little research on whether the VP generates in 2D multilayer materials.…”

“…Two-dimensional (2D) materials attract widespread attention due to their remarkable and compelling physical and chemical properties, and they hold great potential for the development of next-generation electronic devices. − In addition to charge and spin, the valley is a new degree of freedom in 2D materials, which has broad applications in valleytronics such as encoding and storing information. The valley is represented by the local energy extremum of the conduction band (CB) or valence band (VB). − Generally, due to the inherent magnetic exchange interaction and spatial inversion symmetry breaking, the valley polarization (VP) is spontaneously introduced in 2D ferromagnetic systems after considering spin–orbit coupling (SOC). , Valley polarization is prone to occur in several 2D single-layer materials, such as the magnetic VSe 2 , VSSe, AuCl 3 , CeI 2 , RuCl 2 , RuClX (X = F, Br), VSi 2 P 4 , and VGe 2 P 4 monolayers . It is noteworthy that there is very little research on whether the VP generates in 2D multilayer materials.…”