Dynamical stability of two-dimensional metals in the periodic table

Ono, Shota

doi:10.1103/physrevb.102.165424

“…In contrast, (ii) 103 out of 150 unstable compounds have negative E form : for example, CsF (−2.734), LiF (−2.878), RbF (−2.775), and SrO (−2.662) for strongly bonded systems and AlRe (−0.010), CrN (−0.013), and MnAu (−0.010) for weakly bonded systems. A similar issue has been found in a wide variety of materials, such as ordered alloys 26,27 and many two-dimensional materials [28][29][30] . The metastability of materials has to be studied in detail.…”

Section: The M Point Phononssupporting

confidence: 67%

Stability of B2 compounds: Role of the M point phonons

Ono

¹

,

Kobayashi

²

2021

Preprint

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1

0

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Although many binary compounds have the B2 (CsCl-type) structure in the thermodynamic phase diagram, an origin of the structural stability is not understood well. Here, we focus on 416 compounds in the B2 structure extracted from the Materials Project, and study the dynamical stability of those compounds from first principles. We demonstrate that the B2 phase stability lies in whether the lowest frequency phonon at the M point in the Brillouin zone is endowed with a positive frequency. We show that the interatomic interactions up to the fourth nearest neighbor atoms are necessary for stabilizing such phonon modes, which should determine the minimum cutoff radius for constructing the interatomic potentials of binary compounds with guaranteed accuracy.

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“…The stability of the 2D metals has recently been studied in detail 7 – 15 . By focusing on the 2D elemental metals, the author has demonstrated that the concept above (i.e., the 2D structure as a building block for the 3D structures) can hold by using first principles calculations: If the planar hexagonal (HX) structure is dynamically stable, then the BHC, the fcc, and/or the hcp structures are also stable 13 . Po in the square lattice structure is dynamically stable 14 , as a counterpart of Po in the simple cubic structure.…”

Section: Introductionmentioning

confidence: 99%

“…The “stable” structure has no imaginary frequencies within the phonon Brillouin zone. Property 1 Property 2 Example fcc and hcp stable bcc unstable group 3, 4, 10, and 11 27 bcc stable fcc and hcp unstable group 5 and 6 27 HX stable BHC stable group 2, 11, and 12 13 HX stable fcc and hcp stable group 2, 11, and 12 13 BSQ stable fcc and hcp stable group 3, 7, 8, 9, and 10 and Al 13 B synthesized BHC stable IrLi, LiPd, LiPt, and LiRh 15 BHC stable B and L1 stable Cu X with , W, Co, Ni, Cu, Ag, Au, Zn, and Al (this work) B2 stable L1 unstable Cu X with , Rb, group 2 and 3, and Pd (this work) L1 stable B2 unstable Cu X with...…”

Section: Introductionmentioning

confidence: 99%

Metastability relationship between two- and three-dimensional crystal structures: a case study of the Cu-based compounds

Ono

¹

2021

Sci Rep

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Some of the three-dimensional (3D) crystal structures are constructed by stacking two-dimensional (2D) layers. To study whether this geometric concept, i.e., using 2D layers as building blocks for 3D structures, can be applied to computational materials design, we theoretically investigate the dynamical stability of copper-based compounds CuX (a metallic element X) in the B$$_h$$ h and L1$$_1$$ 1 structures constructed from the buckled honeycomb (BHC) structure and in the B2 and L1$$_0$$ 0 structures constructed from the buckled square (BSQ) structure. We demonstrate that (i) if CuX in the BHC structure is dynamically stable, those in the B$$_h$$ h and L1$$_1$$ 1 structures are also stable. Using molecular dynamics simulations, we particularly show that CuAu in the B$$_h$$ h and L1$$_1$$ 1 structures withstand temperatures as high as 1000 K. Although the interrelationship of the metastability between the BSQ and the 3D structures (B2 and L1$$_0$$ 0 ) is not clear, we find that (ii) if CuX in the B2 (L1$$_0$$ 0 ) structure is dynamically stable, that in the L1$$_0$$ 0 (B2) is unstable. This is rationalized by the tetragonal Bain path calculations.

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“…[ 35 ] A phonon band structures calculation performed to understand the dynamical stability of metastable 2D metals (Li to Pb) unveils most transition metals to be stable as buckled honeycomb (bHC) and buckled square (bSQ) lattice, whereas hexagonal (HX) and bHC are the most stable lattices for alkali earth and noble metals in their 2D form. [ 36 ]…”

Section: Introductionmentioning

confidence: 99%

Structure, Stability, Properties, and Application of Atomically Thin Coinage Metal Flatland in Graphene Pore: A Density Functional Theory Calculation

Sangolkar

¹

,

Pawar

²

2021

Physica Status Solidi (b)

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2D metals are emerging materials in the 2D nanomaterials family and a rapid development is seen in the past few years. The properties of material that play a crucial role to determine their application in various fields need to be explored. Herein, a patch consisting of seven to nine coinage metal (Cu, Ag, and Au) atoms is created in the pore of graphene. Electronic properties, work function, and the interaction energy using periodic energy decomposition analysis (pEDA) of the materials are calculated using density functional theory (DFT). Carbon monoxide (CO) adsorption studies on these surfaces are also performed. All the metal atoms are found to align themselves in hexagonal arrangement in the graphene pore. All the materials with an exception of eight‐Au‐patched graphene are found to be metallic. The eight‐Au‐patched graphene is a low bandgap semiconductor exhibiting a direct bandgap of 0.23 eV. CO molecule adsorbs strongly on Cu‐patched surfaces in comparison to Ag‐ and Au‐patched surfaces. The interaction energy of CO is observed to be higher on seven‐Cu‐patched graphene as compared with Ag‐ and Au‐patched graphene.

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Dynamical stability of two-dimensional metals in the periodic table

Cited by 40 publications

References 50 publications

Stability of B2 compounds: Role of the M point phonons

Stability of B2 compounds: Role of the M point phonons

Metastability relationship between two- and three-dimensional crystal structures: a case study of the Cu-based compounds

Structure, Stability, Properties, and Application of Atomically Thin Coinage Metal Flatland in Graphene Pore: A Density Functional Theory Calculation

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