Ultralow-Frequency Collective Compression Mode and Strong Interlayer Coupling in Multilayer Black Phosphorus

Shan Dong, Anmin Zhang, Kai Liu, Jianting Ji, Y. G. Ye, X. G. Luo, X. H. Chen, Xiaoli Ma, Yinghao Jie, Changfeng Chen, Xiaoqun Wang, and Qingming Zhang

Phys. Rev. Lett. 116, 087401 – Published 26 February 2016

Abstract

The recent renaissance of black phosphorus (BP) as a two-dimensional (2D) layered material has generated tremendous interest, but its unique structural characters underlying many of its outstanding properties still need elucidation. Here we report Raman measurements that reveal an ultralow-frequency collective compression mode (CCM) in BP, which is unprecedented among similar 2D layered materials. This novel CCM indicates an unusually strong interlayer coupling, and this result is quantitatively supported by a phonon frequency analysis and first-principles calculations. Moreover, the CCM and another branch of low-frequency Raman modes shift sensitively with changing number of layers, allowing an accurate determination of the thickness up to tens of atomic layers, which is considerably higher than previously achieved by using high-frequency Raman modes. These findings offer fundamental insights and practical tools for further exploration of BP as a highly promising new 2D semiconductor.

Received 31 October 2015

DOI:https://doi.org/10.1103/PhysRevLett.116.087401

Physics Subject Headings (PhySH)

Heterostructures Multilayer thin films Photonic crystals Piezoelectrics

Raman spectroscopy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Shan Dong¹, Anmin Zhang¹, Kai Liu¹, Jianting Ji¹, Y. G. Ye², X. G. Luo^2,6, X. H. Chen^2,5,6, Xiaoli Ma¹, Yinghao Jie¹, Changfeng Chen³, Xiaoqun Wang^4,6, and Qingming Zhang^1,6,*

¹Department of Physics, Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing 100872, People’s Republic of China
²Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, Hefei, Anhui 230026, People’s Republic of China
³Department of Physics and High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, USA
⁴Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
⁵High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, People’s Republic of China
⁶Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People’s Republic of China