Ferromagnetic Semiconductors: VI₃—a New Layered Ferromagnetic Semiconductor (Adv. Mater. 17/2019)

Abstract

Discovering new magnetic materials for the fabrication of 2D device architectures is of great interest. In article number https://doi.org/10.1002/adma.201808074, Tai Kong, Robert J. Cava, and co‐workers report the discovery of a new van der Waals ferromagnetic semiconductor, VI3, which goes through a structural transition at 78 K and a subsequent ferromagnetic transition at 49 K. Stripe‐like ferromagnetic domains on top of larger, structural domains are shown in the back‐cover image.

Honeycomb‐Structure RuI3, A New Quantum Material Related to α‐RuCl3

“…A structural detail is that the normally empty interstitial sites (Ru2, Wyckoff position 3 a ) in a three‐layer honeycomb lattice appear to be occupied by a very small percentage of Ru atoms. Because diffraction experiments of the type typically performed are a time and positional average over the whole crystal, the very small partial occupancy of Ru at position 3 a is likely due to the presence of a small number of stacking faults, [ 26 ] such have often been observed in RuCl 3 . Without constraints among the occupancy parameters in the structure refinement, the honeycomb material freely refines to the slightly Ru‐deficient formula Ru 0.98 I 3 ; the ideal 6 c site of the honeycomb lattice is about 96% occupied while the ideally vacant 3 a site is about 2% occupied.…”

“…We argue that α‐RuI 3 can serve as a new platform for exploring the behavior of a metallic compound for which the consequences of Kitaev spin interactions may be significant, especially when its properties are compared to those of insulating honeycomb RuCl 3 and recently described α‐RuBr 3 . [ 26 ]…”

The Magnetic Genome of Two-Dimensional van der Waals Materials

“…The situation has changed over the past few years with the discovery of layered semiconducting magnetic crystals, like for example CrI 3 5,62,227,383 and VI 3 . 276,277,384 Unconventional magnetism in the semiconducting Mo-based TMD systems 2H-MoTe 2 and 2H-MoSe 2 382 was also recently discovered. These observations suggest an importance of magnetic interactions in electronic structures of TMDs, and extend general commonalities of various unconventional superconductors to this important family of 2D conductor.…”

“…Ferromagnetism below T C ≃ 50 K was also recently discovered in bulk single crystals of VI 3 . 276,405 Similar to other transition-metal trihalides, such as CrI 3 , VI 3 consists of stacked layers in which edgesharing VI 6 octahedra form a honeycomb lattice. This system VI 3 was shown to undergo a structural transition at T s ≃ 78 K, followed by two subsequent FM transitions at T C ≃ 50 K and T C * 36 K upon cooling.…”

Prediction of Chalcogen‐Doped VCl3 Monolayers as 2D Ferromagnetic Semiconductors with Enhanced Optical Absorption

“…[10] Mounet et al predicted 13 easily exfoliable 2D FM semiconductors through the high-throughput materials computation of experimentally known compounds. [11] Then FM semiconductors including CrCl 3 [12] , CrBr 3 [13] , and VI 3 monolayer [14] were synthesized. To further expand the family of 2D FM semiconductors whose number is still limited, researchers try to adjust discovered 2D materials through various methods to achieve new 2D FM semiconductors.…”