Physics

Nanomaterials

Meteorology

Nanotechnology

Heterojunction

Optics

Metamaterial

Thermal resistance

Photon

Composite material

Materials science

Programming language

Thermal

Photonics

Phonon

Condensed matter physics

Layer (electronics)

Graphene

Interfacial thermal resistance

Raman spectroscopy

Computer science

Monolayer

Stack (abstract data type)

Thermal conductivity

Optoelectronics

Thermal insulation

Science Advances

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, MoS2, and WSe2 with thermal resistance greater than 100 times thicker SiO2 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.

Ultrahigh thermal isolation across heterogeneously layered two-dimensional materials