On the in-plane electronic thermal conductivity of biased nanosheet β12-borophene

The unique physical and chemical properties of β₁₂-borophene stem from the coexistence of the Dirac and triplet fermions. The metallic phase of β₁₂-borophene transitions to the semiconducting one when it is subjected to a perpendicular electric field or bias voltage. In this work, with the aid of a five-band tight-binding Hamiltonian, the Green's function approach and the Kubo-Greenwood formalism, the electronic thermal conductivity (ETC) of the semiconducting phase of β₁₂-borophene is studied. Two homogeneous (H) and inversion symmetric (IS) models are considered depending on the interaction of the substrate and boron atoms. In addition, due to the anisotropic structure of β₁₂-borophene, the swapping effect of bias poles is addressed. First of all, we find the pristine ETC^IS < ETC^H independent of the temperature. Furthermore, a decrease of 74.45% (80.62%) is observed for ETC^H (ETC^IS) when strong positive bias voltages are applied, while this is 25.2% (47.48%) when applying strong negative bias voltages. Moreover, the shoulder temperature of both models increases (fluctuates) with the positive (negative) bias voltage. Our numerical results pave the way for setting up future experimental thermoelectric devices in order to achieve the highest performance.

First-principles prediction of chemically functionalized InN monolayers: electronic and optical properties

In this work, we consider the electronic and optical properties of chemically functionalized InN monolayers with F and Cl atoms (i.e., F-InN-F, F-InN-Cl, Cl-InN-F, Cl-InN-Cl monolayers) using first-principles calculations. The adsorption of the F and Cl atoms on the InN monolayer is determined to be chemically stable and the F-InN-F monolayer is most likely to occur. Our calculations show that the chemical functionalization with Cl and F atoms not only breaks the planar structure of InN monolayer but also increases its band gap. By using both Perdew, Burke, and Ernzerhof (PBE) and the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functionals, all four models of chemically functionalized InN monolayers are found to be semiconductors with direct energy gaps and these gaps depend on the constituent species. When the spin-orbit coupling (SOC) was included, the energy gap of these monolayers was reduced and an energy splitting was found at the Γ-point in the valence band. Chemically functionalized InN monolayers can absorb light in a wide region, especially the F-InN-F and Cl-InN-F monolayers have a strong ability to absorb the visible light. Our findings reveal that the chemically functionalized InN monolayers have potential applications in next-generation optoelectronic devices.