Self‐Intercalated Magnetic Heterostructures in 2D Chromium Telluride (Adv. Funct. Mater. 2/2023)

Robust Two-Dimensional Ferromagnetism in Cr5Te8/CrTe2 Heterostructure with Curie Temperature above 400 K

“…The vdW material CrTe 2 has a high Curie temperature, i.e ., 310 K for bulk CrTe 2 , while the Curie temperature reported for Cr 5 Te 8 is usually about 100–165 K . As a comparison, the T c of the 2D vertical Cr 5 Te 8 /CrTe 2 heterostructure surpasses both the bulk counterparts and other 2D Cr x Te y or related heterostructures, suggesting a stronger exchange interaction caused by interfacial magnetic coupling and/or strain-induced lattice distortion, similar to the enhancement of T c in Cr 2 Ge 2 Te 6 and Fe 3 GeTe 2 via applying an external strain or the heterostructures of other 2D magnets. ,− ,, …”

“…High peak intensity with the same plane group indicates high crystalline quality of the flakes with the growth orientation perpendicular to the substrate. Note that although trigonal Cr 5 Te 8 adopts a (2 × 2) supercell of CrTe 2 by self-intercalating a secondary Cr atomic layer into the CrTe 2 backbones, ,, the lattice constants of Cr 5 Te 8 ( a = b = 0.782–792 nm, c = 1.199–1.186 nm) do not show an exactly double relation with those of 1T-CrTe 2 ( a = b = 0.377–0.385 nm, c = 0.617–0.610 nm). ,,,, In addition to the diffraction peaks of CrTe 2 (001), (002), and (003) planes at 14.89°, 29.87°, and 45.41°, additional peaks of the (004) and (006) planes of Cr 5 Te 8 can be observed at ∼29.94° and 45.58° near the CrTe 2 (002) and (003) peaks in the enlarged view of Figure d and Figure S2, suggesting the coexistence of Cr 5 Te 8 and CrTe 2 in the flakes. Besides, the diffraction peaks have an obvious upshift compared to bulk 1T-CrTe 2 and tri-Cr 5 Te 8 , ,, indicating the existence of compressive strain along the c- axis, thus in-plane tensile strain.…”

“…As depicted by atomic structures of tri-Cr 5 Te 8 and 1T-CrTe 2 in Figure i,j, the former is constructed by intercalating half-filling Cr atoms between two adjacent CrTe 2 layers, constituting a (2 × 2) supercell (marked by a red rhombus) compared to CrTe 2 (marked by a yellow rhombus) . This leads to the overlapping of (200), (400), and (600) planes of Cr 5 Te 8 with the (100), (200), and (300) planes of CrTe 2 , which agrees well with the XRD results.…”

“…(e, f) Enlarged view of (b) and (c), respectively. (d) The summary of T c values of the Cr-based 2D ferromagnets and heterostructures. ,,− ,, …”

Controllable Growth of 2D V3S5 Single Crystal by Chemical Vapor Deposition

“…[5][6][7][8] Among these strategies, intercalation method is regarded as an effective way to introduce novel physical properties that do not DOI: 10.1002/adfm.202308356 exist in intrinsic materials due to the tuned electronic structures. For example, the 2D intercalated TMCs such as Cr 1+x Te 2 , Nb 1+x S 2 , Ta x S(Se) y , and V x S y [3,[9][10][11][12][13][14][15][16] have been synthesized. Among them, V x S y family is typical intercalated 2D materials that exhibit various physical properties and hold great potential as promising candidates for spintronic devices.…”