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arXiv · 2201.01701

Confined monolayer Ag as a large gap 2D semiconductor and its momentum resolved excited states

Woojoo Lee·Yuanxi Wang·Wei Qin·Hyunsue Kim·Mengke Liu·T. Nathan Nunley·Bin Fang·Rinu Maniyara·Chengye Dong·Joshua A. Robinson·Vincent Crespi·Xiaoqin Li·Allan H. MacDonald·Chih-Kang Shih
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Abstract

2D materials have intriguing quantum phenomena that are distinctively different from their bulk counterparts. Recently, epitaxially synthesized wafer-scale 2D metals, composed of elemental atoms, are attracting attention not only for their potential applications but also for exotic quantum effects such as superconductivity. By mapping momentum-resolved electronic states using time-resolved and angle-resolved photoemission spectroscopy (ARPES), we reveal that monolayer Ag confined between bilayer graphene and SiC is a large gap (> 1 eV) 2D semiconductor, consistent with GW-corrected density functional theory. The measured valence band dispersion matches the DFT-GW quasiparticle band. However, the conduction band dispersion shows an anomalously large effective mass of 2.4 m0. Possible mechanisms for this large enhancement in the apparent mass are discussed.

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Woojoo Lee, Yuanxi Wang, Wei Qin, Hyunsue Kim, Mengke Liu, T. Nathan Nunley, Bin Fang, Rinu Maniyara, Chengye Dong, Joshua A. Robinson, Vincent Crespi, Xiaoqin Li, Allan H. MacDonald, Chih-Kang Shih. 2022-01-05. Confined monolayer Ag as a large gap 2D semiconductor and its momentum resolved excited states. https://doi.org/10.1021/acs.nanolett.2c02501

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