Tailoring of Interlayer Electronic and Mechanical Coupling in Bilayer MoS₂ by Applying Gigapascal High Pressure

Wei-Ting Hsu^1,6*, Chi-Ruei Pan², Peng-Jen Chen², Josh Leveillee¹, Jiamin Quan¹, Xiaoqin Li¹, Wen-Hao Chang^3,4, Jung-Fu Lin⁵, Feliciano Giustino¹, Mei-Yin Chou², Chih-Kang Shih¹

¹Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
²Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
³Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
⁴Center for Emergent Functional Matter Science (CEFMS), National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
⁵Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78712, USA
⁶Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan

* Presenter:Wei-Ting Hsu, email:wthsu@phys.nthu.edu.tw

Interlayer electronic and mechanical coupling plays a critical role in determining the novel electronic properties of van der Waal (vdW) bilayers. In particular, the coupling strength is determined by the stacking configuration and the interlayer spacing. While the effect of stacking configuration has been well established, the influence of interlayer spacing remains largely unexplored. Here, by measuring the optical absorption and Raman mode of the bilayer MoS₂ in a high-pressure diamond anvil cell, we quantitatively determined the electronic coupling strength as a function of interlayer spacing at various critical points of the Brillouin zone. The pressure dependence of the phonon frequency further reveals the coupling strength of the mechanical coupling between adjacent layers. All experimental data are supported by theoretical calculations. Our work has confirmed the great potential in tailoring vdW bilayers through gigapascal high pressure.

Keywords: van der Waals bilayer, transition metal dichalcogenide, interlayer coupling