First-principles calculations on structural, electronic properties of V-doped 2H-NbSe2

Abstract

Doping strategy has been applied in lots of areas holding promising performance for many functions. Here, we systemically report the main trends in structural, electronic properties and chemical bonding for V doped into 2H-NbSe 2 in two types of doping by means of the first-principles PBE-GGA calculations. To investigate the stability of the doped system with changing concentration of V atoms, 2 Â 2 Â 1, 3 Â 3 Â 1 and 4 Â 4 Â 1 2H-NbSe 2 supercells have been taken into consideration. Results show that it is easier to be doped as the concentration of dopant V is lower and the substituted doping structure is more stable than that of the dopant embedded into the interlayer. In addition, it is found that the dopant V atom forms a covalent bond with the surrounding Se atoms in both of the two doping structures, which can explain the variations of the structural parameters after V atom is doped into 2H-NbSe 2 . Moreover, what leads to the variation of the electronic structures is that the asymmetric structure and the more energetic Se atoms firstly near the dopant V atom after V is doped into 2H-NbSe 2 in both of the two doping types. Our calculation results can provide good theoretical knowledge for the subsequent experiments.

First-principles investigation of the structural and elastic properties of Be12Ti under high pressure

“…Of the beryllium alloys, Be 12 Ti is a promising neutron multiplier for the DEMO blanket since it has a high melting point, low activation, high oxidation resistance, and good compatibility with the structural material of the fusion reactor. [11][12][13][14][15][16][17][18] In this work, the rst principle calculations have been used to investigate structural properties, elastic properties and thermodynamic properties of Be 12 Ti under pressures ranging from 0 to 44 GPa to enhance our understanding of this material. It is well known that pressure is a key factor that inuences the properties of materials during the period of material use, and the deformation behavior of materials under pressure is very interesting.…”

Weak Dimensionality Dependence and Dominant Role of Ionic Fluctuations in the Charge-Density-Wave Transition of NbSe2

“…The presented SSCHA calculations included the entropic effects coming from the ionic fluctuations only, with the electrons kept at 0 K. The good agreement between the experiments and the T CDW obtained with the SSCHA, compared to the extremely high T CDW found at harmonic level (which, on the contrary, included only the electronic fluctuations), suggests that the ionic fluctuations play the dominant role in suppressing the CDW order. However, since in bulk and monolayer NbSe 2 the electronic density of states at the Fermi level is quite sizeable [39,56], mainly due to localized d states, the electronic contribution to entropy is not guaranteed to be negligible when anharmonicty is taken into account. In order to carefully estimate the electronic contribution to the fluctuations also at the anharmonic level, so as to give a quantitative comparison between the ionic and electronic thermal effects, we perform SSCHA calculations including finite-temperature electronic fluctuations.…”

X-ray diffraction and theoretical study of the transition 2H-3R polytypes in Nb1+xSe2 (0 < x < 0.1)

“…It is worth noticing, that the PDOS of Nb-4d is rather broad and almost located at the same energy with Se-4p, suggesting strong interactions. These phenomenon have been observed in some doped and intercalated 2H-NbSe 2 (Chen et al, 2014;Hongping et al, 2014a;Hongping et al, 2014b;Kouarta, Zanat & Belkhir, 2019;Pervin et al, 2020;Xiao-Chen et al, 2020).…”