Toward Exotic Layered Materials: 2D Cuprous Iodide

Abstract

such structures exist under ambient conditions and in total, only a few dozen 2D crystals have been successfully synthesized or exfoliated. While the unusual properties of graphene make it an interesting object of investigation itself, [1] it can also serve as a substrate to stabilize other, less obvious 2D materials. These include materials that do not by themselves form 2D phases, such as the covalent SiO 2 , [2] pseudo-ionic PbI 2 , [3] and metallic CuAu. [4] In the same spirit, layers of graphene have also been used to encapsulate materials. Metal atoms (in some cases forming nitrides [5,6] ) have been intercalated between a monocrystalline SiC surface and graphene to produce 2D metamaterials. [7][8][9] In other studies the encapsulation strategy has been applied in in situ transmission electron microscopy (TEM) observations of dynamics in liquids [10,11] and for protection of electron-beam-sensitive materials. [12,13] In addition, the inert and impermeable graphene envelope can also stabilize 2D layers of weakly bound molecules and atoms, and islands of C 60 fullerenes [14] and noble gases [15] have been Heterostructures composed of 2D materials are already opening many new possibilities in such fields of technology as electronics and magnonics, but far more could be achieved if the number and diversity of 2D materials were increased. So far, only a few dozen 2D crystals have been extracted from materials that exhibit a layered phase in ambient conditions, omitting entirely the large number of layered materials that may exist at other temperatures and pressures. This work demonstrates how such structures can be stabilized in 2D van der Waals (vdw) stacks under room temperature via growing them directly in graphene encapsulation by using graphene oxide as the template material. Specifically, an ambient stable 2D structure of copper and iodine, a material that normally only occurs in layered form at elevated temperatures between 645 and 675 K, is produced. The results establish a simple route to the production of more exotic phases of materials that would otherwise be difficult or impossible to stabilize for experiments in ambient.The ORCID identification number(s) for the author(s) of this article can be found under

Optoelectronic properties of the CuI, AgI and Janus Cu2BrI, and Ag2BrI monolayers by many-body perturbation theory

“…The relaxed lattice constant of CuI, AgI, Cu 2 BrI, and Ag 2 BrI monolayers according to the PBEsol functional is predicted to be 4.059, 4.402, 3.962, and 4.326 Å, respectively. Based on experimental tests [19], the distances between the Cu atomic planes and the Cu-I bond lengths along the in-plane and out-of-plane directions are 1.63±0.35, 2.67±0.16, and 2.55±0.49 Å, respectively, which are in good agreement with the corresponding values of 1.345, 2.642 and 2.566 Å, respectively.…”

“…Interestingly, although strain can slightly alter the symmetries of the structures, no band splitting induced by spin-orbit interaction is observed in these monolayers (Data not shown). The softness of the materials, which was also confirmed in experimental reports [19], is a major obstacle for engineering the band structures and creating the Zeeman-type or Rashba-type spin splitting with strain. Our evaluation shows that applying strain is not a good approach for tuning the properties of CuI and AgI monolayers.…”

“…After the experimental achievement by Mustonen and coworkers [19], we found CuI and AgI monolayers very interesting for exploring their physical properties. These systems belong to the group 11 transition-metal halide MX (M = Cu, Ag, Au; X = Cl, Br, I) 2D lattices, among which MCl and AuX monolayers are thermally and dynamically unstable [37].…”

“…It was also shown that the CuI nanosheets can be synthesized on the 2D substrates like WS 2 and WSe 2 . Mustonen et al [19] successfully synthesized monolayer CuI at ambient conditions by a single-step wet-chemical process between graphene layers. However, the mentioned articles did not provide any information on the electronic and optical properties of CuI.…”

A Materials Scientist's CANVAS: A System for Controlled Alteration of Nanomaterials in Vacuum Down to the Atomic Scale

“…Figure 2 shows an overview of the system. The CANVAS-system allows the controlled alteration of materials [9][10][11][12][13] and even the growth of new ones [14] by utilizing various parts of the system and quickly moving samples between them. Typical workflows include experimental steps like the alteration of a materials by thermal evaporation or plasma irradiation augmented by quick checks at atomic resolution at the STEM.…”