The lattice thermal conductivity in monolayers group-VA: from elements to binary compounds

Abstract

The lattice thermal conductivity ( κ L ) of the monolayers of partial group-VA elements and binary compounds are systemically investigated by the first-principles calculations and phonon Boltzmann transport equation (PBTE), including aW-antimonene, α-arsenene, black phosphorus, α-SbAs, α-SbP and α-AsP. The κ L values decrease with the increasing of atomic mass for these materials with similar geometry and valence structures. It is ascribed to phonon branches softening, low phonon group velocity, and large Grüneisen parameters. Due to the neutralization of phonon group velocity and phonon lifetime, κ L of binary compounds is between their corresponding elements. As the atomic radius and mass increase, the bond strength and the phonon group velocity decreases. Furthermore, the dimensionless parameter γ 2 / A , which comes from the Slack equation and only has the dependence of Grüneisen parameter, grows up with the atomic mass rising, which indicates that a larger anharmonicity is present in the heavier V-V monolayers. For SbAs and SbP compounds, the thermal conductivity anisotropy mainly results from the anisotropy of elastic coefficients along armchair and zigzag directions. Our results highlight the impact of atomic arrangement on the thermal conductivity of group VA binary compounds. This work paves a way to modulate the thermal conductivity of 2D VA elements by incorporation atoms with suitable mass and may guide to improve thermoelectrical performance via the alloying method.

Thermal Conductivity of Buckled and Puckered Arsenene: An Equilibrium Molecular Dynamics (EMD) Simulation

“…The result of thermal conductivity with varying temperatures in the range of 100K, 300K, 500, and 700K in a fixed dimension of 50nmx10nm was shown in Figure 3.4. Notice that, at the temperature of 100K up to 700K the thermal conductivity decreases, which shows similar results to the study in ab-initio and first-principle method [23,24] and in monolayer 2D materials [21,25]. This result also agrees with the thermal conductivity of the puckered arsenene shown in Figure 3.5 For this reason, lattice thermal conductivity has an inverse relationship with temperature [23].…”

Phonon transport in Janus monolayer siblings: a comparison of 1T and 2H-ISbTe

“…In both structures, the optical modes exhibit fascinating behaviour, in which their group velocity is equivalent to or greater than that of their acoustic mode, which is rare among 2D materials. [51][52][53] The maximum group velocity for the optical modes of 1T-ISbTe is determined to be 2.23 km s −1 , which is even greater than its LA and ZA modes, resulting in a contribution of up to 7.63% to the k L from the 8 th optical mode in this structure.…”

Low Thermal Conductivity and High Thermoelectric Performance of Kagome‐Like As and Sb Monolayers: A First‐Principles Study

“…While for β –As and β –Sb, these values are 0.16 and −0.83 respectively. [ 26 ] According to Slack model, [ 27 ] the lattice thermal conductivity is inversely proportional to γ 2 , thus, the larger absolute value of γ for Kagome phase is an indication of lower thermal conductivity.…”