New twisted van der Waals fabrication method based on strongly adhesive polymer

Observations of emergent quantum phases in twisted bilayer graphene prompted a flurry of activities in van-der-Waals (vdW) materials beyond graphene. Most current twisted experiments use a so-called tear-and-stack method using a polymer called PPC. However, despite the clear advantage of the current PPC tear-and-stack method, there are also technical limitations, mainly a limited number of vdW materials that can be studied using this PPC-based method. This technical bottleneck has been preventing further development of the exciting field beyond a few available vdW samples. To overcome this challenge and facilitate future expansion, we developed a new tear-and-stack method using a strongly adhesive polycaprolactone (PCL). With similar angular accuracy, our technique ensures an intrinsically clean interface and low working temperatures. More importantly, it can be applied to many other vdW materials that have remained inaccessible with the PPC-based method. We present our results on twist homostructures made with a wide choice of vdW materials – from two well-studied vdW materials (graphene and MoS₂) to the first-ever demonstrations of other vdW materials (NbSe₂, NiPS₃, and Fe₃GeTe₂). Therefore, our new technique will help expand moiré physics beyond few selected vdW materials and open up more exciting developments.