Penta-C20: A Superhard Direct Band Gap Carbon Allotrope Composed of Carbon Pentagon

Abstract

A metastable sp3-bonded carbon allotrope, Penta-C20, consisting entirely of carbon pentagons linked through bridge-like bonds, was proposed and studied in this work for the first time. Its structure, stability, and electronic and mechanical properties were investigated based on first-principles calculations. Penta-C20 is thermodynamically and mechanically stable, with equilibrium total energy of 0.718 and 0.184 eV/atom lower than those of the synthesized T-carbon and supercubane, respectively. Penta-C20 can also maintain dynamic stability under a high pressure of 100 GPa. Ab initio molecular dynamics (AIMD) simulations indicates that this new carbon allotrope can maintain thermal stability at 800 K. Its Young’s modulus exhibits mechanical anisotropy. The calculated ideal tensile and shear strengths confirmed that Penta-C20 is a superhard material with a promising application prospect. Furthermore, Penta-C20 is a direct band gap carbon based semiconducting material with band gap of 2.89 eV.

First-Principles Study on III-Nitride Polymorphs: AlN/GaN/InN in the Pmn21 Phase

“…First-principles calculations based on density functional theory (DFT) are among the most reliable and popular microscopic theories in material science. This method has a high ability to predict the material structures and properties [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. Yang et al [ 21 ] predicted a novel high-pressure superhard BN phase at high pressure through a developed particle swarm optimization (PSO) algorithm.…”

Quantifying Atomistic Similarity of Carbon Allotropes for Structural Comparison and Classification

“…Additionally, the similarity-based match is performed for a set of crystalline allotropes from the literature − (Figure S7). The pbz/cF288 training allotrope consisting of acetylenes and 6-rings matches the three graphdiyne ( GDY-1 , GDY-2 , and GDY-3 ) crystal structures reported by Matsuoka et al 13 4 6 T10 of the training set and oC14 predicted by Yang et al are determined to be similar, both being tubulanes containing 4-, 6-, and 8-tubes.…”

“…The tP20 in the form of an octahedral tube array, predicted by Fan et al, is found to be structurally similar to 3 3 .4 3 T28 . For other external allotropes, such as tP16 , penta-C20 , o-C240 , oC240 , and oC48 , their best-matched counterparts in the training set are also given in Figure S7.…”

A novel superhard boron nitride polymorph with monoclinic symmetry

“…More and more materials composed of light elements have been found by researchers . Among them, carbon allotrope [1][2][3][4][5][6][7][8][9][10] and boron nitride polymorph [11][12][13][14][15][16] are representatives, and BN polycrystalline materials can be used not only as superhard materials but also as two-dimensional magnets [17]. Recently, a metastable carbon allotrope with sp 3 -hybridized, denoted as Penta-C 20 , was proposed and studied by Zhang et al [1].…”