"A phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, specifically in solids and some liquids."
The quantized lattice vibrations associated with sound or thermal energy in solids.
Lattice vibrations: The study of movement of atoms in a crystal lattice, including the frequencies and modes of vibration.
Crystal symmetry: The study of the symmetry properties of a crystal lattice, including the effects on phonon dispersion and polarization.
Thermal properties: The study of the relationship between thermal properties and phonon behavior, including thermal conductivity, specific heat, and thermal expansion.
Phonon dispersion: The study of the relationship between phonon frequency and wave vector, or the behavior of phonons in different directions in the crystal lattice.
Phonon density of states: The study of the distribution of phonon states in energy space, including the role of defects and impurities.
Polarization: The study of the polarization of phonons and its relation to crystal symmetry.
Interaction with electrons: The study of the interaction between phonons and electrons, including the effects of electron-phonon coupling on thermal and transport properties.
Phonon scattering: The study of the different processes by which phonons can scatter, including anharmonic processes, impurity scattering, and phonon-phonon scattering.
Coherent phonons: The study of the generation and properties of coherent phonons, which are collective excitations of the crystal lattice.
Terahertz spectroscopy: The study of phonon dynamics using terahertz spectroscopy, which uses electromagnetic radiation in the terahertz frequency range to probe the vibrations of the crystal lattice.
Longitudinal phonons: Vibrational modes where the atoms move parallel to the direction of wave propagation. This is the simplest and most common type of phonon.
Transverse phonons: Vibrational modes where the atoms move perpendicular to the direction of wave propagation. These modes are usually present in materials with directional bonding like crystals.
Acoustic phonons: These are sound waves that travel through the material due to longitudinal and transverse vibrations of the atoms. They have low energy and long wavelengths, and are responsible for the thermal conductivity and mechanical properties of the material.
Optical phonons: These phonons correspond to vibrational modes where the charge distribution in the material changes, leading to electromagnetic interactions. These modes require higher energy than acoustic phonons, and play an important role in the band structure of crystals and electronic/optical properties of materials.
Polar phonons: These correspond to optical modes in materials with polar or ionic bonding, where the atoms move together in opposite directions to generate electric dipoles. These modes strongly affect the dielectric properties of the material.
Magnon-phonons: These correspond to vibrations of magnetic moments in certain materials, where the coupling between phonons and magnons results in interesting phenomena like magnetostriction and spin waves.
Superconducting phonons: These are special phonon modes that appear in superconducting materials, where the quantization of lattice vibrations plays a crucial role in the formation and stability of Cooper pairs.
Topological phonons: These are recently discovered modes in topological materials, where the presence of non-trivial topology can lead to protected and exotic types of phonons that are robust against disorder and defects.
"Phonons occur in condensed matter, specifically in solids and some liquids."
"A phonon is a type of quasiparticle, an excited state in the quantum mechanical quantization of the modes of vibrations for elastic structures of interacting particles."
"Phonons, being quasiparticles, are an emergent phenomenon. However, photons are fundamental particles that can be individually detected."
"The study of phonons is an important part of condensed matter physics."
"They play a major role in many of the physical properties of condensed matter systems, such as thermal conductivity and electrical conductivity."
"The concept of phonons was introduced in 1932 by Soviet physicist Igor Tamm."
"The name phonon comes from the Greek word φωνή (phonē), which translates to sound or voice."
"The name is analogous to the word photon representing wave-particle duality for sound waves."
"A phonon is an excited state in the quantum mechanical quantization of the modes of vibrations for elastic structures of interacting particles."
"Phonons can be thought of as quantized sound waves."
"Phonons occur in solids and some liquids."
"Phonons play a major role in many of the physical properties of condensed matter systems, such as thermal conductivity and electrical conductivity."
"They are involved in models of neutron scattering and related effects."
"Phonons, being quasiparticles, are an emergent phenomenon. However, photons are fundamental particles that can be individually detected."
"The name phonon comes from the Greek word φωνή (phonē), which translates to sound or voice."
"Long-wavelength phonons give rise to sound."
"Phonons play a major role in thermal conductivity."
"The study of phonons is an important part of condensed matter physics."
"Phonons can be thought of as quantized sound waves, similar to photons as quantized light waves."