Professor Lifa Zhang published a latest research of chiral phonons in Nano Letters
Recently, Professor Lifa Zhang published his research work of nondegenerate chiral phonons “Nondegenerate chiral phonons in graphene/hexagonal boron nitride heterostructure from first-principles calculations” in the top international journal of Nano Letters (IF=12.080). This is another breakthrough after Professor Lifa Zhang co-published the experimental verification of chiral phonon in Science in February. The first author of this work is Mengnan Gao, a second-year master student of SPT. Lifa Zhang and Wei Zhang are the co-corresponding authors (Wei Zhang is the postdoctor of Lifa Zhang).
Due to the peculiar physics and potential application value, graphene/hexagonal boron nitride heterostructure (G/h-BN) has been widely regarded as a classic, model-like heterostructure. In this work, using the strict analytical derivation and the first-principles calculation, the group of Professor Lifa Zhang systematically studied the phonon chirality ofG/h-BN. It is found that the broken inversion symmetry and the interlayer interaction of G/h-BN not only open the phononic gaps but also lift the degeneracy of left-handed and right-handed chiral phonons at the first-Brillouin-zone valleys. At the same time, the work demonstrate that the vertical stress is effective to tune the degenerated phononic gap while keeping the valley-phonon chirality. This work substantially enrich microscopic understanding of chiral phonons in heterostructures and provide detailed data reference for subsequent Raman measurement, which has important influence and application value in the fields such as 2D materials, valleytronics, phononics and photoelectric transformation.
Professor Lifa Zhangin found the phonon chirality and proposed the valley phonon Hall effect in the system with broken inversion symmetry (PRL 115, 115502 (2015)) in 2015. He then collaborated with the research team of Professor Xiang Zhang, the fellow of the American Academy of Engineering at the university of California, Berkeley, and firstly experimentally observed the chiral phonons (Science 359 (6375), 579 (2018)). Recently, he has successively published a serial works of chiral phonons in the international main-stream Journals such as Phy. Rev. B, New J. Physics, J. Phys. Cond. Matt..