No abstract

No abstract

In this paper, the anisotropic thermal conductivity characteristics of graphene wrinkles are observed for the first time using a non-equilibrium molecular dynamics method. Our results reveal that the wrinkling level has little effect on the thermal conductivity along the wrinkling direction. However, the wrinkling level plays an important role in the reduction of thermal conductivity along the texture direction, which results from the contributions of increased bond length, von Mises stress, broadening of phonon modes and G-band redshift. These results indicate that graphene wrinkles can be a promising candidate to modulate thermal conductivity properties in nanoscale thermal managements and thermoelectric devices.

Black phosphorus (BP), a novel natural two-dimensional layered material with intrinsic in-plane anisotropy, has been attracting significant research attention due to its outstanding electronic and optical properties and tunable bandgaps. Here, an enhancement of near-field radiative heat transfer (NFRHT) arising from a coupling of anisotropic surface plasmon polaritons (SPPs) between two layered BP sheets is demonstrated. The coupling of SPPs along armchair and zigzag directions dominate the NFRHT at near-infrared and mid-infrared frequencies, respectively. The dependence of NFRHT on the number of layers as well as the electron density of BP is then analyzed. It is found that at a small gap size the NFRHT between BP sheets with more number of layers and a higher electron density is lower. While this trend is reversed at a large gap size. Finally, the possibility of using BP to modulate the NFRHT by the mechanical rotation is explored. It is shown that the rotated system exhibits a nonmonotonic dependency of its heat transfer coefficient on the rotation angle, which has never been noted in the noncontact heat exchanges at nanoscale before. This work opens the possibility to apply BP-based materials for active thermal management at the nanoscale.