分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: A fundamental understanding of phonon transport in stanene is crucial to predict the thermal performance in potential stanene-based devices. By combining rst-principle calculation and phonon Boltzmann transport equation, we obtain the lattice thermal conductivity of stanene. A much lower thermal conductivity (11.6W/mK) is observed in stanene, which indicates higher thermoelectric e ciency over other 2D materials. The contributions of acoustic and optical phonons to the lattice thermal conductivity are evaluated. Detailed analysis of phase space for three-phonon processes shows that phonon scattering channels LA + LA/TA/ZA ↔ TA/ZA are restricted, leading to the dominant contributions of high-group-velocity LA phonons to the thermal conductivity. The size dependence of thermal conductivity is investigated as well for the purpose of the design of thermoelectric nanostructures.
提交时间: 2017-05-02
摘要: The intrinsic lattice thermal conductivity of MoS2 is an important aspect in the design of MoS2-based nanoelectronic devices. We investigate the lattice dynamics properties of MoS2 by first-principle calculations. The intrinsic thermal conductivity of sin
分类: 材料科学 >> 材料科学(综合) 提交时间: 2017-05-09
摘要: Solid lubricant coatings have received considerable research attention in space applications owing to their remarkably improved tribological characteristics. But their service life is seriously restricted by the harsh environment, such as high vacuum and abrasive wear. In this paper, a novel design of carbon-based multilayer (MoS2/DLC multilayer) coatings was reported to clarify the friction and wear behavior in high vacuum conditions with and without simulated lunar-dust (SLD). Compared with pure DLC or MoS2 coatings, the multilayer coating showed excellent tribological performance with a low friction coefficient of 0.02 and a wear rate of $6.5 10 6 mm3 N 1 m 1. What is particularly interesting is that the wear volume of MoS2/DLC multilayer coatings with the increase of time is in accordance with the Archard linear law, regardless of the condition with or without SLD. Moreover, the surface morphology and composition of wear tracks and scars reveal that the long life of carbon-based multilayer coatings cannot be explained solely by excellent mechanical performance, and is also attributed to the formation of ridge layers as third body reservoirs and a tribo-induced composite transfer layer containing SLD nanoparticles and coating materials.