Abstract
Stacking and twisting 2D van der Waals (vdW) layers have become versatile platforms to tune the electron correlation. These platforms rely on exfoliating vdW materials down to a single vdW layer and a few vdW layers. We calculate the intrinsic layer-dependent surface and exfoliation energies of typical vdW materials such as graphite, h-BN, black P, MX2(M = Mo or W; X = S, Se, or Te), MX (M = Ga or In; X = S, Se, or Te), Bi2Te3, and MnBi2Te4using density functional theory. For exchange-correlation functionals with explicit vdW interaction, a single vdW layer always has the smallest surface energy, giving a surface energy reduction when compared to that of thicker vdW layers. However, the magnitude of this surface energy reduction quickly decreases with an increase in the number of atomic layers inside the single vdW layer for different vdW materials. Such atomic-layer dependence in surface energy reduction helps explain the different effectiveness of exfoliation for different vdW materials down to a single vdW layer.
| Original language | English |
|---|---|
| Pages (from-to) | 8343-8352 |
| Number of pages | 10 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 16 |
| DOIs | |
| State | Published - Aug 7 2025 |
Funding
This work was supported by the U.S. Department of Energy (DOE) Office of Science, Office of Basic Energy Sciences, through the Ames National Laboratory. The Ames National Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract DE-AC02-07CH11358. J.Y. was supported by the U.S. Department of Energy, Offce of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. J.-X.Q. and S.-Y.X. were supported by the Center for the Advancement of Topological Semimetals, an Energy Frontier Research Center funded by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences, through the Ames National Laboratory under Contract DE-AC02-07CH11358. Some of this research used resources of the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility.