Abstract
Van der Waals (vdW) solids have attracted great attention ever since the discovery of graphene, with the essential feature being the weak chemical bonding across the vdW gap. The nature of these weak interactions is decisive for many extraordinary properties, but it is a strong challenge for current theory to accurately model long-range electron correlations. Here we use synchrotron X-ray diffraction data to precisely determine the electron density in the archetypal vdW solid, TiS2, and compare the results with density functional theory calculations. Quantitative agreement is observed for the chemical bonding description in the covalent TiS2 slabs, but significant differences are identified for the interactions across the gap, with experiment revealing more electron deformation than theory. The present data provide an experimental benchmark for testing theoretical models of weak chemical bonding.
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References
Whittingham, M. S. Lithium batteries and cathode materials. Chem. Rev. 104, 4271–4301 (2004).
Imai, H., Shimakawa, Y. & Kubo, Y. Large thermoelectric power factor in TiS2 crystal with nearly stoichiometric composition. Phys. Rev. B 64, 241104 (2001).
Li, Y., Wang, H., Xie, L., Liang, Y., Hong, G. & Dai, H. MoS2 nanoparticles grown on graphene: an advanced catalyst for the hydrogen evolution reaction. J. Am. Chem. Soc. 133, 7296–7299 (2011).
Hasan, M. Z. & Kane, C. L. Colloquium: topological insulators. Rev. Mod. Phys. 82, 3045–3067 (2010).
Gamble, F. R., DiSalvo, F. J., Klemm, R. A. & Geballe, T. H. Superconductivity in layered structure organometallic crystals. Science 168, 568–570 (1970).
Wilson, J. A., Di Salvo, F. J. & Mahajan, S. Charge-density waves and superlattices in the metallic layered transition metal dichalcogenides. Adv. Phys. 24, 117–201 (1975).
Coleman, J. N. et al. Two-dimensional nanosheets produced by liquid exfoliation of layered materials. Science 331, 568–571 (2011).
Chhowalla, M. et al. The chemistry of two-dimensional layered transition metal dichalcogenide nanosheets. Nat. Chem. 5, 263–275 (2013).
Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 499, 419–425 (2013).
Berland, K. et al. Van der Waals forces in density functional theory: a review of the vdW-DF method. Rep. Prog. Phys. 78, 066501 (2015).
BjörkmanT.., GulansA.., KrasheninnikovA. V.. & NieminenR. M.. Van der Waals bonding in layered compounds from advanced density-functional first-principles calculations. Phys. Rev. Lett. 108, 235502 (2012).
Benedict, L. X. et al. Microscopic determination of the interlayer binding energy in graphite. Chem. Phys. Lett. 286, 490–496 (1998).
Filsø, M. Ø., Eikeland, E., Zhang, J., Madsen, S. R. & Iversen, B. B. Atomic and electronic structure transformations in SnS2 at high pressures: a joint single crystal X-ray diffraction and DFT study. Dalton Trans. 45, 3798–3805 (2016).
Le, N. B., Huan, T. D. & Woods, L. M. Interlayer interactions in van der Waals heterostructures: electron and phonon properties. ACS Appl. Mater. Interfaces 8, 6286–6292 (2016).
Coppens, P. X-ray Charge Densities and Chemical Bonding (Oxford University Press, New York, 1997).
Koritsanszky, T. S. & Coppens, P. Chemical applications of X-ray charge-density analysis. Chem. Rev. 101, 1583–1627 (2001).
Voufack, A. B. et al. When combined X-ray and polarized neutron diffraction data challenge high-level calculations: spin-resolved electron density of an organic radical. Acta Crystallogr. B 73, 544–549 (2017).
Jørgensen, M. R. V. et al. Contemporary X-ray electron-density studies using synchrotron radiation. IUCrJ 1, 267–280 (2014).
Wahlberg, N. et al. Synchrotron powder diffraction of silicon: high-quality structure factors and electron density. Acta Crystallogr. A 72, 28–35 (2016).
Bader, R. F. W. Atoms in Molecules – A Quantum Theory (Oxford University Press, Oxford, 1990).
Trevey, J. E., Stoldt, C. R. & Lee, S.-H. High power nanocomposite TiS2 cathodes for all-solid-state lithium batteries. J. Electrochem. Soc. 158, A1282–A1289 (2011).
Hansen, N. K. & Coppens, P. Testing aspherical atom refinements on small-molecule data sets. Acta Crystallogr. A 34, 909–921 (1978).
Fischer, A. et al. Experimental and theoretical charge density studies at subatomic resolution. J. Phys. Chem. A 115, 13061–13071 (2011).
Gatti, C. Chemical bonding in crystals: new directions. Z. Kristallogr. 220, 399–457 (2005).
Johnson, E. R. et al. Revealing noncovalent interactions. J. Am. Chem. Soc. 132, 6498–6506 (2010).
Saleh, G., Gatti, C., Lo Presti, L. & Contreras-García, J. Revealing non-covalent interactions in molecular crystals through their experimental electron densities. Chem. Eur. J. 18, 15523–15536 (2012).
Pike, N. A. et al. Origin of the counterintuitive dynamic charge in the transition metal dichalcogenides. Phys. Rev. B 95, 201106 (2017).
Brandenburg, J. G. et al. Geometrical correction for the inter- and intramolecular basis set superposition error in periodic density functional theory calculations. J. Phys. Chem. A 117, 9282–9292 (2013).
Rimmington, H. P. B., Balchin, A. A. & Tanner, B. K. Nearly perfect single crystals of layer compounds grown by iodine vapour-transport techniques. J. Cryst. Growth 15, 51–56 (1972).
Sugimoto, K. et al. Extremely high resolution single crystal diffractometory for orbital resolution using high energy synchrotron radiation at SPring-8. AIP Conf. Proc. 1234, 887–890 (2010).
Blessing, R. H. An empirical correction for absorption anisotropy. Acta Crystallogr. A 51, 33–38 (1995).
Blessing, R. H. Outlier treatment in data merging. J. Appl. Cryst. 30, 421–426 (1997).
Sheldrick, G. M. Crystal structure refinement with SHELXL. Acta Crystallogr. C 71, 3–8 (2015).
Blaha, P., Schwarz, K., Madsen, G. K. H., Kvasnicka, D. & Luitz, J. WIEN2k, an Augmented Plane Wave plus Local Orbitals Program for Calculating Crystal Properties (Technical University of Wien, 2001).
Sun, J., Ruzsinszky, A. & Perdew, J. P. Strongly constrained and appropriately normed semilocal density functional. Phys. Rev. Lett. 115, 036402 (2015).
Perdew, J. P. & Zunger, A. Self-interaction correction to density-functional approximations for many-electron systems. Phys. Rev. B 23, 5048–5079 (1981).
Perdew, J. P. & Wang, Y. Accurate and simple analytic representation of the electron-gas correlation energy. Phys. Rev. B 45, 13244–13249 (1992).
Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).
Peng, H., Yang, Z.-H., Perdew, J. P. & Sun, J. Versatile van der Waals density functional based on a meta-generalized gradient approximation. Phys. Rev. X 6, 041005 (2016).
Vydrov, O. A. & Van Voorhis, T. Nonlocal van der Waals density functional: the simpler the better. J. Chem. Phys. 133, 244103 (2010).
Sabatini, R., Gorni, T. & de Gironcoli, S. Nonlocal van der Waals density functional made simple and efficient. Phys. Rev. B 87, 041108 (2013).
Hamada, I. Van der Waals density functional made accurate. Phys. Rev. B 89, 121103 (2014).
Lee, K., Murray, É. D., Kong, L., Lundqvist, B. I. & Langreth, D. C. Higher-accuracy van der Waals density functional. Phys. Rev. B 82, 081101 (2010).
Klimeš, J., Bowler, D. R. & Michaelides, A. Van der Waals density functionals applied to solids. Phys. Rev. B 83, 195131 (2011).
Tran, F., Stelzl, J., Koller, D., Ruh, T. & Blaha, P. Simple way to apply nonlocal van der Waals functionals within all-electron methods. Phys. Rev. B 96, 054103 (2017).
Otero-de-la-Roza, A., Johnson, E. R. & Luaña, V. Critic2: a program for real-space analysis of quantum chemical interactions in solids. Comput. Phys. Commun. 185, 1007–1018 (2014).
Otero-de-la-Roza, A., Blanco, M. A., Pendás, A. M. & Luaña, V. Critic: a new program for the topological analysis of solid-state electron densities. Comput. Phys. Commun. 180, 157–166 (2009).
Otero-de-la-Roza, A. & Luaña, V. A fast and accurate algorithm for QTAIM integration in solids. J. Comput. Chem. 32, 291–305 (2011).
Volkov, A. et al. XD2006 – a computer program package for multipole refinement, topological analysis of charge densities and evaluation of intermolecular energies from experimental and theoretical structure factors (2006).
Abramov, Y. A. On the possibility of kinetic energy density evaluation from the experimental electron-density distribution. Acta Crystallogr. A 53, 264–272 (1997).
Sabino, J. R. & Coppens, P. On the choice of d-orbital coordinate system in charge-density studies of low-symmetry transition-metal complexes. Acta Crystallogr. A 59, 127–131 (2003).
Acknowledgements
This work was supported by the Danish National Research Foundation (DNRF93), the Danish Center for Synchrotron and Neutron Science (DanScatt), the JSPS Bilateral Open Partnership Joint Research Projects for 2015−2017 and 2017−2019, the International Education and Research Laboratory Program and the International Tenure Track system of Univ. Tsukuba. The synchrotron experiment was performed at SPring-8 BL02B1 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) as a Partner User (Proposal No: 2015A0078). The theoretical calculations were performed at the Center for Scientific Computing, Aarhus.
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B.B.I designed and coordinated this study. M.Ø.F. synthesized the samples; H.K., K.T., M.S., V.R.H. and K.S. performed the experiments; H.K. and K.T. analyzed the data, with discussions with M.S., V.R.H., J.O., E.N. and B.B.I.; J. Z. and S.C. performed the theoretical calculations. H.K. and B.B.I. wrote the manuscript. All authors discussed the experimental results and contributed to the manuscript.
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Kasai, H., Tolborg, K., Sist, M. et al. X-ray electron density investigation of chemical bonding in van der Waals materials. Nature Mater 17, 249–252 (2018). https://doi.org/10.1038/s41563-017-0012-2
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DOI: https://doi.org/10.1038/s41563-017-0012-2
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