Observation of Low-Frequency Interlayer Breathing Modes in Few-Layer Black Phosphorus

• Main Authors: Ling, Xi (Contributor), Liang, Liangbo (Author), Huang, Shengxi (Contributor), Puretzky, Alexander A. (Author), Geohegan, David B. (Author), Sumpter, Bobby G. (Author), Kong, Jing (Contributor), Meunier, Vincent (Author), Dresselhaus, Mildred (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science (Contributor), Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Research Laboratory of Electronics (Contributor)
• Format: Article
• Language: English
• Published: American Chemical Society (ACS), 2016-01-10T19:44:59Z.
• Subjects: Article
• Online Access: Get fulltext

As a new two-dimensional layered material, black phosphorus (BP) is a very promising material for nanoelectronics and optoelectronics. We use Raman spectroscopy and first-principles theory to characterize and understand the low-frequency (LF) interlayer breathing modes (<100 cm[superscript -1]) in few-layer BP for the first time. Using a laser polarization dependence study and group theory analysis, the breathing modes are assigned to A[subscript g] symmetry. Compared to the high-frequency (HF) Raman modes, the LF breathing modes are considerably more sensitive to interlayer coupling and, thus, their frequencies show a stronger dependence on the number of layers. Hence, they constitute an effective means to probe both the crystalline orientation and thickness of few-layer BP. Furthermore, the temperature dependence shows that in the temperature range −150 to 30 °C, the breathing modes have a weak anharmonic behavior, in contrast to the HF Raman modes that exhibit strong anharmonicity.
National Science Foundation (U.S.) (DMR-1004147)
National Science Foundation (U.S.) (DE-SC0001299)