Pseudo-atomic orbital based tight-binding model investigation of Fermi Arcs in Na3Bi.
ORAL
Abstract
Na3Bi is a topological Dirac semimetal [1] initially thought to have double surface Fermi arcs on facets with momentum separated surface projected Dirac points [1-3]. Angle resolved photoemission spectroscopy (ARPES) measurements on Na3Bi's (100) facet [4] are consistent with double surface Fermi arcs, although they could not determine whether there are Dirac points with a characteristic cusp at the connection point [1,2]. However, it was shown that bulk symmetry preserving terms that leave the Dirac points unchanged could deform the double surface Fermi arcs into a closed Fermi contour that does not connect to the Dirac points [5] and could be still consistent with the ARPES data.
We examine the effect of surfaces in a realistic model of Na3Bi. We construct a first-principles based tight binding model using pseudo-atomic orbitals [6]. For a 60-layer (100) neutral termination slab, near a surface projected bulk Dirac point, we find states with surface and bulk extent. Away from the projected Dirac points we find slab termination localized states. Such behavior, along with the surface and bulk bands converging towards the expected bulk Dirac point for thicker neutral termination (100) slabs, is consistent with the predicted behavior of Fermi arcs in Na3Bi.
1. Z. Wang, et al, Phys. Rev. B 85, 195320 (2012).
2. A. C. Potter, I. Kimchi, and A. Vishwanath, Nature Communications 5, 5161 (2014).
3. E. V. Gorbar, V. A. Miransky, I. A. Shovkovy, and P. O. Sukhachov, Phys. Rev. B 91, 121101 (2015).
4. S.-Y. Xu, et al, Science 347 (2015).
5. M. Kargarian, M. Randeria, and Y.-M. Lu, Proceedings of the National Academy of Sciences 113 (2016).
6. M. Buongiorno Nardelli, et al, Computational Materials Science 143 (2018).
We examine the effect of surfaces in a realistic model of Na3Bi. We construct a first-principles based tight binding model using pseudo-atomic orbitals [6]. For a 60-layer (100) neutral termination slab, near a surface projected bulk Dirac point, we find states with surface and bulk extent. Away from the projected Dirac points we find slab termination localized states. Such behavior, along with the surface and bulk bands converging towards the expected bulk Dirac point for thicker neutral termination (100) slabs, is consistent with the predicted behavior of Fermi arcs in Na3Bi.
1. Z. Wang, et al, Phys. Rev. B 85, 195320 (2012).
2. A. C. Potter, I. Kimchi, and A. Vishwanath, Nature Communications 5, 5161 (2014).
3. E. V. Gorbar, V. A. Miransky, I. A. Shovkovy, and P. O. Sukhachov, Phys. Rev. B 91, 121101 (2015).
4. S.-Y. Xu, et al, Science 347 (2015).
5. M. Kargarian, M. Randeria, and Y.-M. Lu, Proceedings of the National Academy of Sciences 113 (2016).
6. M. Buongiorno Nardelli, et al, Computational Materials Science 143 (2018).
* We thank the Illinois Physics department for funding.We thank the Illinois Campus Cluster for computational resources.
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Presenters
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Vasilios K Passias
University of Illinois at Urbana-Champaign
Authors
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Vasilios K Passias
University of Illinois at Urbana-Champaign
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Lucas K Wagner
University of Illinois at Urbana-Champaign, Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA, University of Illinois at Urbana-Champaign.