Phonons carrying intrinsic angular momentum represent a frontier in condensed matter physics. This series covers the theory, materials, experimental detection, and applications of chiral phonons—from valley-phonon coupling in 2D materials to phonon angular momentum transport.
Chiral phonons are lattice vibrations that carry angular momentum. They were theoretically predicted in 2015 (Zhang & Niu, PRL 115, 115502), and their first widely cited experimental observation in a 2D material was reported in 2018 for monolayer WSe₂ (Zhu et al., Science 359, 579). Unlike conventional phonons described by scalar displacement fields, chiral phonons exhibit circular atomic motion and can couple to valley degrees of freedom in 2D materials. This emerging field connects phonon physics with topology, valleytronics, and quantum information science.
Fundamental theory of chiral phonons including phonon angular momentum, symmetry requirements, Berry phase connection, and group theory analysis.
Chiral phonons in 2D transition metal dichalcogenides, valley-phonon coupling, and 3D chiral crystals like α-quartz and tellurium.
Experimental techniques for probing chiral phonons including circularly polarized Raman spectroscopy, circular dichroism, and ultrafast methods.
Computational methods for phonon chirality and applications in valleytronics, phonon angular momentum transport, and emerging device concepts.
This educational content was generated with AI assistance for the Hashimoto Lab knowledge base. While efforts have been made to ensure accuracy, readers should verify critical information with primary sources and peer-reviewed literature.