Abstract
Most two-dimensional (2D) materials experimentally studied so far have hexagons as their building blocks. Only a few exceptions, such as PdSe2, are lower in energy in pentagonal phases and exhibit pentagons as building blocks. Although theory has predicted a large number of pentagonal 2D materials, many of these are metastable and their experimental realization is difficult. Here we report the successful synthesis of a metastable pentagonal 2D material, monolayer pentagonal PdTe2, by symmetry-driven epitaxy. Scanning tunnelling microscopy and complementary spectroscopy measurements are used to characterize this material, which demonstrates well-ordered low-symmetry atomic arrangements and is stabilized by lattice matching with the underlying Pd(100) substrate. Theoretical calculations, along with angle-resolved photoemission spectroscopy, reveal monolayer pentagonal PdTe2 to be a semiconductor with an indirect bandgap of 1.05 eV. Our work opens an avenue for the synthesis of pentagon-based 2D materials and gives opportunities to explore their applications such as multifunctional nanoelectronics.
| Original language | English |
|---|---|
| Pages (from-to) | 1339-1346 |
| Number of pages | 8 |
| Journal | Nature Materials |
| Volume | 23 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2024 |
Funding
L.L., D.Y.Z. and Y.P.C. acknowledge partial financial support by the US Department of Energy (Office of Basic Energy Sciences) under award number DE-SC0019215 (for synthesis) and Multidisciplinary University Research Initiatives (MURI) Program under award number FA9550-20-1-0322 (for characterizations). Y.J. and Y.L. acknowledge support by the Natural Science Foundation of Jiangsu Province (BK20200873, BZ2020011) and the National Natural Science Foundation of China (grants number 22173067). M.B., J.A.M. and P.H. acknowledge support by VILLUM FONDEN via the Centre of Excellence for Dirac Materials (grant number 11744). L.L., R.B. and Y.P.C. also acknowledge support by VILLUM FONDEN via the Villum Investigator Program (grant number 25931). Part of the STM measurements (at low temperature) were performed in the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. We express our gratitude to the Center for Nanoscale Materials of Argonne National Laboratory and in particular to N. P. Guisinger for the help with the STM tip preparation. We also acknowledge helpful discussions with E. D. B\u00F8jesen, C. Bugge, R. E. Diaz, Y. Ikuhara, L. H. Klausen, T. Koyama, A. Kumatani, K. K. Neelisetty and the team at Thermo Fisher Scientific, Y. Ouyang, M. Saito and J. Smith.