The quest for materials and devices that are capable of controlling heat flux continues to fuel research on thermal controlling devices. In this letter, using molecular dynamics simulations, we demonstrate that a part...The quest for materials and devices that are capable of controlling heat flux continues to fuel research on thermal controlling devices. In this letter, using molecular dynamics simulations, we demonstrate that a partially clamped singlelayer graphene can serve as a thermal modulator. The mismatch in phonon dispersion between the unclamped and clamped graphene sections results in phonon interface scattering, and the strength of interface scattering is tunable by controlling the clamp-graphene distance via applying the external pressure. Owing to the ultra-thin structure of graphene and its highly sensitive phonon dispersion to external physical interaction, the modulation efficiency--which is defined as the ratio of the highest to lowest heat flux-can reach as high as 150% at a moderate pressure of 50 GPa. This modulation efficiency can be further enhanced by arranging a number of clamps in series along the direction of the heat flux.展开更多
The thermal conductance across the one-dimensional （1D） interface between a MoS2 monolayer and Au electrode （edge-contact） has been investigated using molecular dynamics simulations. Although the thermal conductiv...The thermal conductance across the one-dimensional （1D） interface between a MoS2 monolayer and Au electrode （edge-contact） has been investigated using molecular dynamics simulations. Although the thermal conductivity of monolayer MoS2 is 2-3 orders of magnitude lower than that of graphene, the covalent bonds formed at the interface enable interfacial thermal conductance （ITC） that is comparable to that of a graphene-metal interface. Each covalent bond at the interface serves as an independent channel for thermal conduction, allowing ITC to be tuned linearly by changing the interfacial bond density （controlling S vacancies）. In addition, different Au surfaces form different bonding configurations, causing large ITC variations. Interestingly, the S vacancies in the central region of MoS2 only slightly affect the ITC, which can be explained by a mismatch of the phonon vibration spectra. Further, at room temperature, ITC is primarily dominated by phonon transport, and electron-phonon coupling plays a negligible role. These results not only shed light on the phonon transport mechanisms across 1D metal-MoS2 interfaces, but also provide guidelines for the design and optimization of such interfaces for thermal management in MoS2-based electronic devices.展开更多
文摘The quest for materials and devices that are capable of controlling heat flux continues to fuel research on thermal controlling devices. In this letter, using molecular dynamics simulations, we demonstrate that a partially clamped singlelayer graphene can serve as a thermal modulator. The mismatch in phonon dispersion between the unclamped and clamped graphene sections results in phonon interface scattering, and the strength of interface scattering is tunable by controlling the clamp-graphene distance via applying the external pressure. Owing to the ultra-thin structure of graphene and its highly sensitive phonon dispersion to external physical interaction, the modulation efficiency--which is defined as the ratio of the highest to lowest heat flux-can reach as high as 150% at a moderate pressure of 50 GPa. This modulation efficiency can be further enhanced by arranging a number of clamps in series along the direction of the heat flux.
文摘The thermal conductance across the one-dimensional （1D） interface between a MoS2 monolayer and Au electrode （edge-contact） has been investigated using molecular dynamics simulations. Although the thermal conductivity of monolayer MoS2 is 2-3 orders of magnitude lower than that of graphene, the covalent bonds formed at the interface enable interfacial thermal conductance （ITC） that is comparable to that of a graphene-metal interface. Each covalent bond at the interface serves as an independent channel for thermal conduction, allowing ITC to be tuned linearly by changing the interfacial bond density （controlling S vacancies）. In addition, different Au surfaces form different bonding configurations, causing large ITC variations. Interestingly, the S vacancies in the central region of MoS2 only slightly affect the ITC, which can be explained by a mismatch of the phonon vibration spectra. Further, at room temperature, ITC is primarily dominated by phonon transport, and electron-phonon coupling plays a negligible role. These results not only shed light on the phonon transport mechanisms across 1D metal-MoS2 interfaces, but also provide guidelines for the design and optimization of such interfaces for thermal management in MoS2-based electronic devices.
