Vaziri Sam, Yalon Eilam, Muñoz Rojo Miguel, Suryavanshi Saurabh V, Zhang Huairuo, McClellan Connor J, Bailey Connor S, Smithe Kirby K H, Gabourie Alexander J, Chen Victoria, Deshmukh Sanchit, Bendersky Leonid, Davydov Albert V, Pop Eric
Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA.
Theiss Research Inc., La Jolla, CA 92037, USA.
Sci Adv. 2019 Aug 16;5(8):eaax1325. doi: 10.1126/sciadv.aax1325. eCollection 2019 Aug.
Heterogeneous integration of nanomaterials has enabled advanced electronics and photonics applications. However, similar progress has been challenging for thermal applications, in part due to shorter wavelengths of heat carriers (phonons) compared to electrons and photons. Here, we demonstrate unusually high thermal isolation across ultrathin heterostructures, achieved by layering atomically thin two-dimensional (2D) materials. We realize artificial stacks of monolayer graphene, MoS, and WSe with thermal resistance greater than 100 times thicker SiO and effective thermal conductivity lower than air at room temperature. Using Raman thermometry, we simultaneously identify the thermal resistance between any 2D monolayers in the stack. Ultrahigh thermal isolation is achieved through the mismatch in mass density and phonon density of states between the 2D layers. These thermal metamaterials are an example in the emerging field of phononics and could find applications where ultrathin thermal insulation is desired, in thermal energy harvesting, or for routing heat in ultracompact geometries.
纳米材料的异质集成推动了先进电子学和光子学应用的发展。然而，类似的进展在热应用领域却颇具挑战，部分原因在于与电子和光子相比，热载流子（声子）的波长更短。在此，我们展示了通过堆叠原子级薄的二维（2D）材料实现的超薄异质结构中异常高的热隔离性能。我们制备了单层石墨烯、二硫化钼（MoS）和二硒化钨（WSe）的人工堆叠结构，其热阻比100倍厚的二氧化硅（SiO）还要大，在室温下的有效热导率低于空气。利用拉曼热成像技术，我们同时确定了堆叠结构中任意二维单层之间的热阻。超高热隔离是通过二维层之间质量密度和声子态密度的不匹配实现的。这些热超材料是声子学新兴领域的一个范例，可应用于需要超薄热绝缘的场合、热能收集，或在超紧凑几何结构中进行热路由。
