Novel 2D ferroelastic SnNX (X = Cl, Br) monolayers with anisotropic high carrier mobility and excellent thermoelectric transport properties

Abstract

In recent years, layered FeOCl-type materials have attracted considerable attention for their excellent thermoelectric properties. The electronic structure and thermoelectric properties of SnNX (X = Cl, Br) monolayers as a...

Four-Phonon Enhanced the Thermoelectric Properties of ScSX (X = Cl, Br, and I) Monolayers

“…The results for ScSX monolayers are listed in Table and the relevant parameters of other FeOCl-type materials are also listed for comparison. The anisotropy of carrier mobility can be evaluated by the anisotropic ratio R a = μ normalM μ normalm , where μ M and μ m denote the maximum and minimum carrier mobility of electrons (holes), respectively. , The calculated R a values of ScSCl, ScSBr, and ScSI monolayers are 132.52 (1.36), 75.16 (1.33), and 1543.82 (2.30) for electrons (holes), respectively, which are larger than those of other reported 2D FeOCl-type materials, such as the SnNCl monolayer [ R a = 19.35 (6.67)] . Interestingly, the R a value of the ScSI monolayer is significantly larger than the two others due to its small mobility of electrons along the y -axis, which is consistent with previous study .…”

“…16 (1.33), and 1543.82 (2.30) for electrons (holes), respectively, which are larger than those of other reported 2D FeOCl-type materials, such as the SnNCl monolayer [R a = 19.35 (6.67)]. 55 Interestingly, the R a value of the ScSI monolayer is significantly larger than the two others due to its small mobility of electrons along the y-axis, which is consistent with previous study. 33 This result indicates that the carriers along the different transport directions are well separated.…”

A multifunctional Mg2Si monolayer with negative Poisson's ratio and ultrahigh thermoelectric performance at room temperature

“…The DP theory is also used in the calculations of carrier mobility and the carrier relaxation time for recently reported materials. 80–82 The calculated method and results for carrier mobilities are listed in the ESI †. Apparently, the Mg 2 Si monolayer shows great anisotropy in the in-plane direction.…”

A First-Principles Study of 2D Bi-Based BiOClBr, BiOClI, and BiOBrI Monolayers with Ultralow Lattice Thermal Conductivities for Thermoelectric Application

“…The DP constant E 1 describes the variation of the band edges (VBM and CBM) with uniaxial strain and is determined by E 1 = E edge /∂(Δ a / a 0 ), where E edge is the band edge shift. Based on the parabolic fit of the band structure at the VBM and CBM, we estimated the carrier effective mass by using the formula m * = ℏ 2 /(∂ 2 E ( k )/∂ k 2 ), where E ( k ) represents the Kohn–Sham eigenenergy with the wave vector k . , The carrier mobility μ can be obtained as a relation to the relaxation time μ = τ e m * . Table lists the calculated results for all the above-mentioned parameters of the BiOClBr, BiOClI, and BiOBrI monolayers at 300 K. It is evident that the m * of the hole is greater than that of the electron for all three monolayers, consistent with the different features between the VBM and CBM mentioned above.…”