First-principles studies on phase stability of TiO2 by using GGA+U calculations

2018 ◽  
Author(s):  
M. H. Samat ◽  
M. F. M. Taib ◽  
N. K. Jaafar ◽  
O. H. Hassan ◽  
M. Z. A. Yahya ◽  
...  
Keyword(s):  
Phase Stability ◽  
First Principles

First-principles equation of state and phase stability of niobium pentoxide

2014 ◽  
Vol 81 ◽  
pp. 133-140 ◽  
Author(s):  
C. Valencia-Balvín ◽  
S. Pérez-Walton ◽  
G.M. Dalpian ◽  
J.M. Osorio-Guillén
Keyword(s):  
Equation Of State ◽  
Phase Stability ◽  
First Principles ◽  
Niobium Pentoxide

Phase stability, Debye temperature and hardness of semiconducting manganese tetraboride MnB4: First-principles investigations

2017 ◽  
Vol 31 (20) ◽  
pp. 1750131 ◽  
Author(s):  
Ming-Min Zhong ◽  
Cheng Huang ◽  
Chun-Ling Tian
Keyword(s):  
Debye Temperature ◽  
Phase Stability ◽  
First Principles ◽  
Formation Enthalpy ◽  
Structural Features ◽  
High Melting Point ◽  
Fundamental Understanding ◽  
New Perspective ◽  
The Relationship ◽  
Good Agreement

First-principles investigations are employed to provide a fundamental understanding of the structural features, phase stability, mechanical properties, Debye temperature, and hardness of manganese tetraboride. Eight candidate structures of known transition-metal tetraborides are chosen to probe. The calculated lattice parameters, elastic properties, Poisson’s ratio, and [Formula: see text] ratio are derived. It is observed that the monoclinic structure with [Formula: see text] symmetry (MnB4–MnB4) is the most stable in energy. The mechanical and thermodynamic stabilities of seven possible phases are confirmed by the calculated elastic constants and formation enthalpy. Moreover, the analysis on density of states demonstrates semiconducting behavior of MnB4–MnB4 and different metallic behaviors of other phases. The estimated hardness of MnB4–MnB4 is 38.3 GPa, which is in good agreement with experimental value. Furthermore, the relationship between hardness and Debye temperature is investigated and verifies that MnB4–MnB4 is a newly potential semiconducting ultrahard material with high melting point. It provides a new perspective of searching for semiconducting superhard materials to be applied in extreme conditions.

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