Stability and electronic properties of gallenene

Kutana, Alex; Altalhi, Tariq; Ruan, Qiyuan; Zhang, Jun-Jie; Penev, Evgeni S.; Yakobson, Boris I.

doi:10.1039/d1na00553g

Cited by 7 publications

(3 citation statements)

References 33 publications

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“…The wavering stability of 2D metals makes experiments challenging, whereby research relies heavily on computations. A reasonable description of metallic bonding requires electronic structure simulations, which has made the densityfunctional theory (DFT) [15,16] the workhorse method for modeling 2D metals [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Most DFT studies have chosen plane wave (PW) basis sets [32] and the nonempirical Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional [33].…”

Section: Introductionmentioning

confidence: 99%

Optimizing density-functional simulations for two-dimensional metals

Abidi

Koskinen

2022

Phys. Rev. Materials

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Unlike covalent two-dimensional (2D) materials like graphene, 2D metals have nonlayered structures due to their nondirectional, metallic bonding. While experiments on 2D metals are still scarce and challenging, densityfunctional theory (DFT) provides an ideal approach to predict their basic properties and assist in their design. However, DFT methods have rarely been benchmarked against metallic bonding at low dimensions. Therefore, to identify optimal DFT attributes for a desired accuracy, we systematically benchmark exchange-correlation functionals from LDA to hybrids and basis sets from plane waves to local basis with different pseudopotentials. With 1D chain, 2D honeycomb, 2D square, 2D hexagonal, and 3D bulk metallic systems, we compare the DFT attributes using bond lengths, cohesive energies, elastic constants, densities of states, and computational costs. Although today most DFT studies on 2D metals use plane waves, our comparisons reveal that local basis with often-used Perdew-Burke-Ernzerhof exchange correlation is quite sufficient for most purposes, while plane waves and hybrid functionals bring limited improvement compared to the greatly increased computational cost. These results ease the demands for generating DFT data for better interaction with experiments and for datadriven discoveries of 2D metals incorporating machine learning algorithms.

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Section: Introductionmentioning

confidence: 99%

Optimizing density-functional simulations for two-dimensional metals

Abidi

Koskinen

2022

Phys. Rev. Materials

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“…The absence of imaginary modes in phonon dispersions of TiB 2 , VB 2 , FeB 2 , ZrB 2 , HfB 2 , and WB 2 implies the dynamical stability of these MBenes, as presented in figure S1 of supplementary material, while few MBenes contains large imaginary frequencies (ScB 2 , CrB 2 , MnB 2 , YB 2 , and MoB 2 , as presented in figure S1 of supplementary material) indicating their dynamical instability. However, low imaginary frequencies (small negative spectra) have been observed near the Γ point for NbB 2 and TaB 2 , which are often regarded as artifacts and observed in phonon spectra of 2D systems, as observed in borophene monolayer which has been recently synthesized [38], and in 2D gallium (gallenene) [39] as well, both of which are regarded as stable 2D materials. In the experimental manifestations, such small imaginary frequencies can be removed by applying small strain or depositing the 2D layer onto proper substrate with minimal lattice mismatch [38,40].…”

Section: Structural and Stability Analysismentioning

confidence: 99%

Electronic and elastic correlations in AlB₂-type two-dimensional hexagonal MBenes

Sharma,

Rangra

2023

J. Phys.: Condens. Matter

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With the advent of MXenes as two-dimensional (2D) materials beyond graphene, non carbonic 2D materials analogically referred as MBenes have significantly attracted researchers’ attention. Such 2D MBenes remains largely unexplored. Here, we systematically investigate electronic and elastic properties of 2D transition metal (TM) based AlB2-type hexagonal MBenes consisting of a honeycomb networked graphene like boron layer embedded with diverse TM atoms at center. First we determine the thermodynamic, dynamic, thermal, and mechanical stability of MBenes, considering a wide range of 3d, 4d, and 5d TM elements. Electronic and elastic calculations are performed for stable MBenes in order to parameterize and investigate the interdependence of properties. Elastic calculations predicts the brittle-ductile nature and bond character of MBenes while unraveling the in-plane auxetic behavior. Our electronic calculations predict the metallic band nature for 2D VB2, NbB2, TaB2, and WB2 along with previously reported dirac points in 2D TiB2, FeB2, ZrB2, and HfB2. The elastic and electronic calculations clearly indicates the non-directional metallic bonds and intrinsically ductile nature of 2D-FeB2 distinct from other MBenes. Subsequently we performed a covariance analysis to assess the correlation amongst the observables of interest and further establish the interdependence of the properties. Our calculations for elastic correlations also suggests that mechanical brittle-ductile nature and auxetic behavior of MBenes can be tuned by strain engineering of the elastic constants. Our results further suggests that strong correlations between Poisson ratio and d state electrons can be utilized to tune the auxetic behavior by careful doping of the materials. Our work demonstrates the weak elastic-electronic correlations, suggesting that the strain engineering can be utilized for the tailored behavior of MBenes for practical applications. Thus, our systematic analysis of the mechano-elastic and electronic properties of 2D hexagonal MBenes and their correlations advance our understandings of emergent 2D family.

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“…[9] Recently, ultrathin gallium films, also known as gallenene, have received considerable interests due to the potential application in the emerging elemental 2D materials. [10][11][12][13][14][15][16][17][18][19][20] By means of solid-melt exfoliation, Kochat et al fabricated the atomically thin gallium films, i.e., gallenene sheets, on silicon substrates. [10] Tao et al realized the epitax-ial growth of gallenene monolayer on the Si(111)-√ 3× √ 3-Ga template.…”

Section: Introductionmentioning

confidence: 99%

Epitaxial growth of ultrathin gallium films on Cd(0001)

Li 李,

Shi 石,

Yao 姚

et al. 2024

Chinese Phys. B

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The growth and electronic properties of ultrathin Ga films on Cd(0001) have been investigated by a low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. It is found that Ga films exhibit the epitaxial growth with the pseudomorphic 1×1 lattice. The Ga islands deposited at 100 K show a ramified shape due to the suppressed edge diffusion and corner crossing. Furthermore, the majority of Ga islands reveal flat tops and a preferred height of three atomic layers, indicating the electronic growth at low temperature. Annealing to room temperature leads to not only the growth mode transition from electronic growth to conventional Stranski-Krastanov growth, but also the shape transition from ramified islands to smooth compact islands. Scanning tunneling spectroscopy (STS) measurements reveal that the Ga monolayer exhibits a metallic behavior. DFT calculations indicate that all the interfacial Ga atoms occupy the energetically favorable hcp-hollow sites of substrate. The charge density difference analysis demonstrates that the charge transfer from the Cd substrate to the Ga atoms is negligible, and there is weak interaction between Ga atoms and the Cd substrate. These results shall shed important light on the fabrication of ultrathin Ga films on metal substrates with novel physical properties.

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Stability and electronic properties of gallenene

Abstract: Two-dimensional metals offer intriguing possibilities to explore metallicity and other related properties in systems with reduced dimensionality. Here, following recent experimental reports of synthesis of two-dimensional metallic gallium (gallenene) on...

Cited by 7 publications

References 33 publications

Optimizing density-functional simulations for two-dimensional metals

Optimizing density-functional simulations for two-dimensional metals

Electronic and elastic correlations in AlB₂-type two-dimensional hexagonal MBenes

Epitaxial growth of ultrathin gallium films on Cd(0001)

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Stability and electronic properties of gallenene

Abstract: Two-dimensional metals offer intriguing possibilities to explore metallicity and other related properties in systems with reduced dimensionality. Here, following recent experimental reports of synthesis of two-dimensional metallic gallium (gallenene) on...

Cited by 7 publications

References 33 publications

Optimizing density-functional simulations for two-dimensional metals

Optimizing density-functional simulations for two-dimensional metals

Electronic and elastic correlations in AlB2-type two-dimensional hexagonal MBenes

Epitaxial growth of ultrathin gallium films on Cd(0001)

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Product

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Electronic and elastic correlations in AlB₂-type two-dimensional hexagonal MBenes