Mechanism Regulating Self-Intercalation in Layered Materials

Abstract

Recent experimental breakthrough demonstrated a powerful synthesis approach for intercalating the van der Waals gap of layered materials to achieve property modulation, thereby opening an avenue for exploring new physics and devising novel applications, but the mechanism governing intercalant assembly patterns and properties remains unclear. Based on extensive structural search and energetics analysis by ab initio calculations, we reveal a Sabatier-like principle that dictates spatial arrangement of self-intercalated atoms in transition metal dichalcogenides. We further construct a robust descriptor quantifying that strong intercalant-host interactions favor a monodispersing phase of intercalated atoms that may exhibit ferromagnetism, while weak interactions lead to a trimer phase with attenuated or quenched magnetism, which further evolves into tetramer and hexagonal phases at increasing intercalant density. These findings elucidate the mechanism underpinning experimental observations and paves the way for rational design and precise control of self-intercalation in layered materials.

Unraveling the mechanism of vanadium self-intercalation in 1T-VSe2: atomic-scale evidence for phase transition and superstructure model for intercalation compound

“…The migration occurs randomly with the vast majority of intercalated V i atoms located at the octahedral sites (yellow square) and few at the tetrahedral sites (cyan square), implying that tetrahedral site may serve as an intermediate state during the migration of intercalated V i atom (from an octahedral site to its neighboring one) as illustrated in figure 4(d). This observation is also in consistent with early theoretical studies that the octahedral sites are energy-favored sites for metal intercalation, rather than the tetrahedral sites [35].…”

“…To visualize the structures of the multi-phase concurrent product, cross-sectional atomically resolved iDPC-STEM images along the the interlayer octahedral site which is regarded as the most energy-favored intercalation sites [23,35]. Specifically in VSe, the interlayer octahedral sites are fully filled by V i as shown in figures 2(d), (h) and (l), corresponding to an arrangement of 1 × 1 and an intercalation ratio of 100%.…”

Enhancing Metallicity and Basal Plane Reactivity of 2D Materials via Self-Intercalation

“…An alternative functionalization strategy consists of intercalating foreign or native atoms into the vdW gap of a multilayer structure. In general, this scheme can produce significant changes to the material properties thanks to the strong covalent bonds formed between the host 2D layers and the intercalated atoms. − In particular, it is expected that intercalation can enhance interlayer interactions, induce doping of the 2D materials, strongly modify their electronic structure and chemical reactivity, or even convert them into distinctly different structural phases.…”

Surface Stability and Exfoliability of Non-van der Waals Magnetic Chromium Tellurides

“…The general formula of chromium tellurides can be written as Cr 1−δ Te, and δ represents the proportion of Cr vacancies compared with Cr atoms in CrTe. From the perspective of layered structures, their structures can also be viewed as being formed by self-intercalation of layered CrTe 2 materials. , Figure shows the crystal structures of several non-vdW Cr 1−δ Te, including CrTe (δ = 0), Cr 3 Te 4 (δ = 0.25), Cr 2 Te 3 (δ = 0.333), and Cr 5 Te 8 (δ = 0.375), and their calculated lattice constants are summarized in Table S1. Cr atoms are represented by alternating layers of blue (Cr1 layer) and cyan spheres (Cr2 layer) in Figure , and blue spheres form a perfect close-packed triangular lattice, while cyan spheres have a different concentration of Cr vacancies compared to the blue spheres.…”

“…From the perspective of layered structures, their structures can also be viewed as being formed by selfintercalation of layered CrTe 2 materials. 33,34 Figure 1…”