Observation of Interlayer Phonons in Transition Metal Dichalcogenide Atomic Layers and Heterostructures

POSTER

Abstract

Interlayer phonon modes in atomically thin transition metal dichalcogenide (TMD) heterostructures were observed for the first time. We measured the low-frequency Raman response of MoS2/WSe2 and MoSe2/MoS2 heterobilayers. We discovered a distinctive Raman mode (30 - 35 cm-1) and identified this new Raman mode as the layer breathing mode (LBM) arising from the perpendicular vibration between the two TMD layers. We also investigated the ultralow-frequency Raman response of atomically thin ReS2, a special type of TMD with unique distorted 1T structure. We found that the two shear modes in bilayer ReS2 are nondegenerate and clearly resolved in the Raman spectrum, in contrast to the doubly degenerate shear modes in other two-dimensional materials. By carrying out comprehensive first-principles calculations, we can account for the frequency and Raman intensity of the interlayer modes and determine the stacking order in bilayer ReS2.

Authors

  • Ye Gaihua

    Univ of Northern Iowa

  • Swapan Chattopadhyay

    Gravitational Astrophysics Lab, NASA Goddard Space Flight Center, Northern Illinois University and Argonne National Laboratory, Northern Illinois University, None, Monmouth College, IL, University of California Santa Cruz, Southern Illinois University Carbondale, Argonne National Laboratory, University of Iowa, Sinop University, Bingol University, Univ of Northern Iowa, University of California, Riverside, University of Northern Iowa, University of Wisconsin, Fairfield University, North Central College

  • Swapan Chattopadhyay

    Gravitational Astrophysics Lab, NASA Goddard Space Flight Center, Northern Illinois University and Argonne National Laboratory, Northern Illinois University, None, Monmouth College, IL, University of California Santa Cruz, Southern Illinois University Carbondale, Argonne National Laboratory, University of Iowa, Sinop University, Bingol University, Univ of Northern Iowa, University of California, Riverside, University of Northern Iowa, University of Wisconsin, Fairfield University, North Central College

  • Swapan Chattopadhyay

    Gravitational Astrophysics Lab, NASA Goddard Space Flight Center, Northern Illinois University and Argonne National Laboratory, Northern Illinois University, None, Monmouth College, IL, University of California Santa Cruz, Southern Illinois University Carbondale, Argonne National Laboratory, University of Iowa, Sinop University, Bingol University, Univ of Northern Iowa, University of California, Riverside, University of Northern Iowa, University of Wisconsin, Fairfield University, North Central College