Electronic and transport properties of semimetal ZrBeSi crystal: a first-principles study

Abstract

In recent years, semimetals have aroused people's research interest. Here, we systematically study phonon and electronic transport properties of the ZrBeSi with semimetal character by using the first-principles calculations together with the Boltzmann transport theory. Calculated lattice thermal conductivities of the ZrBeSi along a and c axes are 31.3 W/m· K and 56.0 W/m· K at room temperature, respectively, which are larger than the most semiconductors and semimetals. By comparing with other semimetals, we find that the larger lattice thermal conductivity of ZrBeSi is due to its smaller Grüneisen parameter, which indicates the weaker phonon scattering. Main contributions to the lattice thermal conductivities along a and c axis come from the acoustic branches, and conversely, the contributions of optical branches are very small. In addition, we calculate the Seebeck coefficient and the electron thermal conductivity of ZrBeSi based on the relaxation time approximation. The electronic transport properties of ZrBeSi exhibit strong anisotropy in both a and b directions. Calculated electronic thermal conductivities of pristine ZrBeSi along a and c axes are 8.8 W/m· K and 9.7 W/m· K at room temperature, respectively. Furthermore, we also obtain the figure of merit (ZT) on the basis of phonon and electron transport. The obtained ZT along c axis reaches a maximum of 0.11 at 900 K, demonstrating that ZrBeSi has a general ZT, but it has good heat conduction ability. Our research will help to understand the transport properties of semimetals and expand the application of semimetals to heat conduction devices. At the same time, it also provides some reference for the future experimental work.

Ultralow lattice thermal conductivity, negative thermal expansion, elastic and thermoelectric properties of Lanthanum Nitride: Insights from first-principle calculations

“…A denser k-point grid of 19 19 19 ´´mesh has been considered for electronic band structure and density of states (DOS) calculations. To precisely estimate the relativistic effect of heavy La atom, the spin-orbit coupling (SOC) correction has been incorporated.…”

“…Recent study on LaN further reveals its importance in activating nitrogen for ammonia synthesis [1]. Interestingly, the other lanthanum monopnictide compounds (LaP, LaAs, LaBi) show fascinating thermoelectric performances due to their lower lattice thermal conductivity ( l k ) and higher thermoelectric figure of merit (ZT) [8-10].Exploring the l k and ZT of the 3D materials from the first-principle calculations or experimental observations not only provide wealth insights for their futuristic applications in clean and global energy conservation, but may help to understand the underpinning physics which drive their thermoelectric performances [11][12][13][14][15][16][17][18][19][20][21][22]. Besides, the materials with both ultralow l k and negative thermal expansion (NTE) show remarkable applications in thermoelectric conversion systems, power semiconductor devices and in fuel cells [17,[23][24][25][26].…”

“…Exploring the l k and ZT of the 3D materials from the first-principle calculations or experimental observations not only provide wealth insights for their futuristic applications in clean and global energy conservation, but may help to understand the underpinning physics which drive their thermoelectric performances [11][12][13][14][15][16][17][18][19][20][21][22]. Besides, the materials with both ultralow l k and negative thermal expansion (NTE) show remarkable applications in thermoelectric conversion systems, power semiconductor devices and in fuel cells [17,[23][24][25][26].…”