Phase transitions, elastic and electronic properties of hydrogen storage Na2PdH4

2021 ◽  
Vol 47 (12) ◽  
pp. 1037-1040
Author(s):  
S. Al ◽  
C. Kurkcu
2014 ◽  
Vol 97 (12) ◽  
pp. 4011-4018 ◽  
Author(s):  
Felipe A. La Porta ◽  
Lourdes Gracia ◽  
Juan Andrés ◽  
Júlio R. Sambrano ◽  
Jose A. Varela ◽  
...  

2015 ◽  
Vol 112 (22) ◽  
pp. 6898-6901 ◽  
Author(s):  
Matthew J. Lyle ◽  
Chris J. Pickard ◽  
Richard J. Needs

We predict by first-principles methods a phase transition in TiO2 at 6.5 Mbar from the Fe2P-type polymorph to a ten-coordinated structure with space group I4/mmm. This is the first report, to our knowledge, of the pressure-induced phase transition to the I4/mmm structure among all dioxide compounds. The I4/mmm structure was found to be up to 3.3% denser across all pressures investigated. Significant differences were found in the electronic properties of the two structures, and the metallization of TiO2 was calculated to occur concomitantly with the phase transition to I4/mmm. The implications of our findings were extended to SiO2, and an analogous Fe2P-type to I4/mmm transition was found to occur at 10 TPa. This is consistent with the lower-pressure phase transitions of TiO2, which are well-established models for the phase transitions in other AX2 compounds, including SiO2. As in TiO2, the transition to I4/mmm corresponds to the metallization of SiO2. This transformation is in the pressure range reached in the interiors of recently discovered extrasolar planets and calls for a reformulation of the equations of state used to model them.


Author(s):  
Dušica Jovanović ◽  
Dejan Zagorac ◽  
Branko Matović ◽  
Aleksandra Zarubica ◽  
Jelena Zagorac

Recent studies of TiO2/TiS2 nanostructures with various morphologies have been reported, usually showing improved properties with applications from electronics and catalysis to solar cells and medicine. However, there is a limited number of studies on the crystal structures of TiO2/TiS2 compounds with corresponding properties. In this research, relevant crystal structures of TiO1–x S x (x = 0, 0.25, 0.5, 0.75 and 1) solid solutions were investigated using an ab initio method. For each composition, crystal structures adopting anatase, rutile and CdI2 structure type were calculated on LDA-PZ and GGA-PBE levels of theory. Novel phase transitions and predicted structures are presented, and apart from several interesting metastable structures, a very interesting pressure-induced phase transition is found in the TiOS compound. Furthermore, electronic properties were studied through the dependence of semiconducting properties on dopant concentration. The first description of the electronic properties of the mixed TiO1–x S x compounds in crystal form has been presented, followed by a detailed study of the structure–property relationship, which will possibly have numerous industrial and technological applications.


2020 ◽  
Vol 124 (27) ◽  
pp. 14804-14810
Author(s):  
Komsilp Kotmool ◽  
Prutthipong Tsuppayakorn-aek ◽  
Thanayut Kaewmaraya ◽  
Udomsilp Pinsook ◽  
Rajeev Ahuja ◽  
...  

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