First-principles calculations of phonon behaviors in graphether: a comparative study with graphene

Abstract

Recently, a two-dimensional (2D) oxocarbon monolayer, graphether, is arousing extensive attentions owing to the excellent electrical properties. In this work, we calculate lattice thermal conductivities (k) of graphether and graphene...

Thermal Properties of 2D Dirac Materials MN4 (M = Be and Mg): A First-Principles Study

“…For a more intuitive comparison, the average phonon group velocities of BeN 4 and MgN 4 monolayers are calculated, which are 3.61 km s –1 and 3.27 km s –1 in the whole frequency region, respectively, which are lower than that of graphene monolayer (7.09 km s –1 ). 39 Particularly, the average phonon group velocities of high frequency phonons of BeN 4 and MgN 4 monolayers are 3.04 km s –1 and 2.89 km s –1 , which are smaller than the values of low frequency phonons (6.05 km s –1 and 4.16 km s –1 ), indicating that the low frequency phonons have a large contribution to lattice thermal conductivity. According to eq 1 , in comparison with MgN 4 monolayer, BeN 4 monolayer has a higher lattice thermal conductivity because of the higher phonon group velocity.…”

“…On the basis of our previous work, the isotropic lattice thermal conductivity of graphene at 300 K is 3544.41 W m –1 K –1 , which is much larger than the values of BeN 4 and MgN 4 monolayers. 39 On the other hand, high temperature will monotonically decline the lattice thermal conductivities of these monolayers. As the temperature increases from 300 to 900 K, the lattice thermal conductivities of BeN 4 and MgN 4 monolayers along the armchair and zigzag directions are reduced to 236.47 W m –1 K –1 and 171.66 W m –1 K –1 , 26.27 W m –1 K –1 and 7.96 W m –1 K –1 , respectively.…”

A robust spin-dependent Seebeck effect and remarkable spin thermoelectric performance in graphether nanoribbons

“…8,10,11 Over recent years, the SDSE has been widely studied in devices based on two-dimensional materials, e.g., graphene, 12,13 silicene, 14 boron-nitrogen, 15 phosphorene, 16 and CrI 3 monolayer, 17 and they are reported to have different kinds of potential applications, for instance, spin rectifiers and spin diodes. 14,18 Recently, a novel two-dimensional material, graphether, [19][20][21][22] has been reported to possess excellent electrical, thermal and mechanical performance. Zhu et al 19 demonstrated the design for the fabrication of graphether by the bottom-up assembly of dimethyl ether molecules, and the Pt(100) surface could be used as a suitable substrate.…”

Virtual Vibrational Analytics of Reduced Graphene Oxide

“…As shown by the DOV trendline, the vibration spectrum was clearly divided into two parts from 20 to 1100 cm −1 and from 1100 to 1800 cm −1 , respectively. This two-part character of the vibration spectrum of NGMs also remained in the crystalline state [21,26,27].…”

“…The matter was connected with a typical size-effect concerning the Raman spectra of substances based on covalent bonds when the substance nature is transformed from an amorphic to a crystalline one [30,31]. In fact, when the linear dimension of the domains achieved and/or exceeded L ph ~15 nm, which is a free path of the high-frequency optical phonon of the graphene crystal [8,27], the domain dynamics acquired the characteristic features of crystalline behavior and the Raman spectra tended to adopt a single-band appearance in favor of the G-band corresponding to the asymmetrical sp 2 C-H stretching.…”