Abstract:
In this study, we have investigated the properties of Cu3VSe4, a sulvanite material, in
both its cubic and tetragonal phases by implementing first-principles computations
founded on density functional theory. Our calculations reveal that the cubic phase's
lattice parameters are a = b = c = 5.62 Å, while the tetragonal phase has lattice
parameters are a = b = 5.77 Å and c/a = 1.032, which corresponds to c = 5.95 Å. Both
phases are found to be thermodynamically stable and non-magnetic in their intrinsic
form. The band gaps of the cubic and tetragonal phases are 0.91 eV (M-X) and 0.62
eV (R-X), respectively, and both are indirect in nature. We have also studied the total
density of states (DOS) in company with, the partial density of states (PDOS) of both
phases, and figure 4.6 provides a detailed insight into the nature of the compound.
Moreover, we have used the semi-local Boltzmann transport theory to derive various
thermoelectric properties of the two phases of Cu3VSe4 at different temperatures,
including the Seebeck coefficient (S), conductivity (σ), power factor (PF), electronic
thermal conductivity (кe), and figure of merit (ZT), as mentioned in equation 1.6. Our
results indicate that the cubic phase of Cu3VSe4 has a ZT value of 0.716 for n-type at a
temperature range of 750-900 K and 0.67 for p-type at 1200 K. On the other hand, the
tetragonal phase exhibits a ZT value of 0.959 for n-type at 857 K and 0.788 for p-type
xxii
at 900 K. These ZT values demonstrate that both phases of Cu3VSe4 are highly
suitable for thermoelectric applications.
In addition, the effects of strain (ε=0, ±5, ±10) on the cubic phase are are quite
astonishing as with the increase or decrease in strain electronic properties i.e band gap
values of cubic Cu3VSe4, also increase or decrease. The variation in the electronic
properties also influence the thermoelectric properties of this phase.
In summary, our analysis provides valuable insights into the properties of Cu3VSe4 in
both its cubic and tetragonal phases and highlights the potential of this material for
thermoelectric applications.
