TITLE:
A First Principles Investigation of the Mechanical Properties of g-TlN
AUTHORS:
Qing Peng, Chao Liang, Wei Ji, Suvranu De
KEYWORDS:
g-TlN; Mechanical Properties; High Order Elastic Constants; Density Functional Theory; 2D Materials
JOURNAL NAME:
Modeling and Numerical Simulation of Material Science,
Vol.2 No.4,
October
22,
2012
ABSTRACT: We investigate the structure and mechanical properties of proposed graphene-like hexagonal thallium nitride monolayer (g-TlN) using first-principles calculations based on density-functional theory. Compared to graphene-like hexagonal boron nitride monolayer (g-BN), g-TlN is much softer, with 12% in-plane stiffness, 25%, 22%, and 20% ultimate strengths in armchair, zigzag, and biaxial strains respectively. However, g-TlN has a larger Poisson’s ratio, 0.69, about 3.1 times that of g-BN. It was found that the g-TlN also sustains much smaller strains before rupture. We obtained the second, third, fourth, and fifth order elastic constants for a rigorous continuum description of the elastic response of g-TlN. The second order elastic constants, including in-plane stiffness, are predicted to monotonically increase with pressure while the Poisson’s ratio monotonically decreases with increasing pressure.