|Title||0 Ultralow-frequency Raman system down to 10 cm(-1) with longpass edge filters and its application to the interface coupling in t(2+2)LGs|
|Affiliation||Chinese Acad Sci, Inst Semicond, State Key Lab Superlattices & Microstruct, Beijing 100083, Peoples R China.|
Nanjing Tech Univ NanjingTech, Key Lab Flexible Elect KLOFE, 30 South Puzhu Rd, Nanjing 211816, Jiangsu, Peoples R China.
Nanjing Tech Univ NanjingTech, IAM, Jiangsu Natl Synerget Innovat Ctr Adv Mat SICAM, 30 South Puzhu Rd, Nanjing 211816, Jiangsu, Peoples R China.
Peking Univ, Sch Phys, Collaborat Innovat Ctr Quantum Matter, Ctr Nanochem, Beijing 100871, Peoples R China.
|Keywords||TWISTED MULTILAYER GRAPHENE|
FOLDED ACOUSTIC PHONONS
|Publisher||REVIEW OF SCIENTIFIC INSTRUMENTS|
|Citation||REVIEW OF SCIENTIFIC INSTRUMENTS.2016,87(5).|
|Abstract||Ultralow-frequency (ULF) Raman spectroscopy becomes increasingly important in the area of two-dimensional (2D) layered materials; however, such measurement usually requires expensive and nonstandard equipment. Here, the measurement of ULF Raman signal down to 10 cm(-1) has been realized with high throughput by combining a kind of longpass edge filters with a single monochromator, which are verified by the Raman spectrum of L-cystine using three laser excitations. Fine adjustment of the angle of incident laser beam from normal of the longpass edge filters and selection of polarization geometry are demonstrated how to probe ULF Raman signal with high signal-to-noise. Davydov splitting of the shear mode in twisted (2+2) layer graphenes (t(2+2)LG) has been observed by such system in both exfoliated and transferred samples. We provide a direct evidence of twist-angle dependent softening of the shear coupling in t(2+2)LG, while the layer-breathing coupling at twisted interfaces is found to be almost identical to that in bulk graphite. This suggests that the exfoliation and transferring techniques are enough good to make a good 2D heterostructures to demonstrate potential device application. This Raman system will be potentially applied to the research field of ULF Raman spectroscopy. Published by AIP Publishing.|
|Appears in Collections:||物理学院|