Computational Dissection of Two-Dimensional Rectangular Titanium Mononitride TiN: Auxetics and Promises for Photocatalysis

Abstract

Recently, two-dimensional (2D) transition-metal nitrides have triggered an enormous interest for their tunable mechanical, optoelectronic, and magnetic properties, significantly enriching the family of 2D materials. Here, by using a broad range of first-principles calculations, we report a systematic study of 2D rectangular materials of titanium mononitride (TiN), exhibiting high energetic and thermal stability due to in-plane d-p orbital hybridization and synergetic out-of-plane electronic delocalization. The rectangular TiN monolayer also possesses enhanced auxeticity and ferroelasticity with an alternating order of Possion's Ratios, stemming from the competitive interactions of intra- and inter- Ti-N chains. Such TiN nanosystem is a n-type metallic conductor with specific tunable pseudogaps. Halogenation of TiN monolayer downshifts the Fermi level, achieving the optical energy gap up to 1.85 eV for TiNCl(Br) sheet. Overall, observed electronic features suggest that the two materials are potential photocatalysts for water splitting application. These results extend emerging phenomena in a rich family 2D transition-metal-based materials and hint for a new platform for the next-generation functional nanomaterials.

Hydrogenation Induced Carrier Mobility Polarity Reversal in Monolayer AlN

“…In addition, mechanical properties are also crucial for the practical application of 2D materials, therefore, we briefly analyzed the effect of full hydrogenation on the elastic constants of 1L‐AlN (see Table S2, Supporting Information). Our numerical results (Table S2, Supporting Information) show that the terms ( C 11 , C 12 , C 2 2 , and C 66 ) and Young's modulus ( Y 2D ) of 1L‐AlN‐H 2 are smaller than those of 1L‐AlN, consistent with the conclusion that sp 3 hybridized orbitals (1L‐AlN‐H 2 ) is “softer” than sp 2 hybridized orbitals (1L‐AlN) …”

Analysis of the Deformation Behavior and Mechanical Properties of Slit‐Perforated Auxetic Metamaterials

“…In addition, their mechanical properties are scale independent since they are governed by their structure, geometry and designs which are themselves scale independent. In recent years, there has been a great increase in interest in these materials due to their suitability for a number of biomedical, electronic, and aerospace applications …”

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

“…The corresponding first absorption peaks in the absorption spectra are the optical band gaps at 2.01 and 1.72 eV, respectively. Thus the calculated exciton binding energies [ 43 – 45 ] are 0.25 and 0.14 eV for SiAs 2 and GeAs 2 , respectively. Semiconductors with exciton energies in this range of a few hundred millielectronvolts are supposed to play a key role in photovoltaic applications [ 46 ].…”