Phonon anharmonicities in 7-armchair graphene nanoribbons

Investigation of the Electron–Phonon Coupling in Dirac Semimetal PdTe2 via Temperature‐Dependent Raman Spectroscopy

“…The contribution of Δω an j can be interpreted using a multiphonon scattering approach that combines 3-and 4-ph decay processes. [25,29] Δω an…”

“…[30] As the temperature increases, the occupations of states below E F become less, and those above E F become more, leading to the decreasing linewidth with temperature. The anharmonic linewidth contribution could be expressed as [25,29] Γ j anh ðTÞ ¼…”

“…The contribution of can be interpreted using a multiphonon scattering approach that combines 3‐ and 4‐ph decay processes. [ 25,29 ] in which and denote the 3‐ and 4‐ph anharmonic fitting constants, respectively. and .…”

“…In contrast, the 3‐ph decay process (pink dashed–dotted line) exhibits blueshift, similar to the behaviors of some nanomaterials such as graphene, [ 26,30 ] graphite, [ 30,31 ] and 7‐armchair graphene nanoribbons (AGNRs). [ 29 ] It can be seen that some of the data points for the frequency shift may spread out of the whole fitting line in the temperature range of 80–300 K, which may be because of changes in the laser spot on the exfoliated PdTe 2 surface or the vibration of the local Raman stage at low temperatures. [ 32,33 ] All parameters associated with E g mode frequency fitting are extracted as 1.5 10 −2 cm −1 , 10 −2 cm −1 , and the bare phonon frequency 74.71 cm −1 , respectively.…”

“…Similar trends have been observed in the carbon‐based materials such as graphite, [ 31 ] graphene, [ 30 ] and 7‐AGNRs. [ 29 ] It is well known that for a defect‐free sample, phonons can decay into lower‐energy phonons via phonon–phonon (ph–ph) interaction due to the anharmonicity in lattice vibrational potentials or into the creation of electron–hole pairs via e–ph coupling. Therefore, E g mode linewidth broadening can be expressed as follows.…”