Tunable phonon polaritons in boron nitride nanoscrolls [Invited]

We theoretically demonstrate that boron nitride nanoscrolls (BNSs) – one-dimensional nanostructures formed by rolling boron nitride nanosheets into scroll-like architectures – can serve as a platform for phonon polariton studies. Specifically, two types of phonon polaritons (PhPs), namely those propagating along the axial direction (i.e., propagating PhPs) and those resonating in the circumferential direction (i.e., localized PhPs), are identified in BNSs. Moreover, both modes can be effectively manipulated by altering structural parameters such as the number of turns and radius. Particularly, their application in vibrational strong coupling with organic molecules is predicted. Our results not only expand the family of polaritonic materials but also establish a framework for polariton studies in other van der Waals nanoscrolls.