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Band alignment at the CaF2/Si(111) interface through advanced electronic structure calculations

Thomas Bischoff1*, Igor Reshetnyak1*, Alfredo Pasquarello1*

1 Chaire de Simulation à l'Echelle Atomique (CSEA), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

* Corresponding authors emails: thomas.bischoff@epfl.ch, igor.reshetnyak@epfl.ch, alfredo.pasquarello@epfl.ch
DOI10.24435/materialscloud:m4-by [version v1]

Publication date: Jul 13, 2020

How to cite this record

Thomas Bischoff, Igor Reshetnyak, Alfredo Pasquarello, Band alignment at the CaF2/Si(111) interface through advanced electronic structure calculations, Materials Cloud Archive 2020.74 (2020), doi: 10.24435/materialscloud:m4-by.


We determine the band alignment at the CaF2/Si(111) interface through various advanced electronic-structure methods. This interface is experimentally well-studied and serves as an ideal test case to examine the accuracy of theoretical schemes. We use both global and range-separated hybrid functionals as well as GW calculations including self-consistency and vertex corrections. Our calculation procedure accounts for residual strain resulting from the small mismatch in the lateral lattice constants at the interface to minimize the systematic error in the comparison with experiment. Both the hybrid-functional and the GW schemes give band alignments in overall good agreement with the experimental characterization. However, the considered methods yield sizable variations in the calculated band offsets, which do not originate from incorrect evaluations of the band gaps but rather from different inherent relative positions of the band edges. The comparison with experiment reveals that the global hybrid functional and the quasiparticle self-consistent GW with vertex corrections give the most accurate description of the band alignment. We then determine the variation of the band offsets as a function of the amount of excess fluorine at the interface and attribute the experimental spread in the measured offsets to uncontrolled fluorine contamination.

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File name Size Description
340.5 KiB Pseudopotentials for Si, Ca, and F in both upf and psp8 format
2.4 KiB Quantum ESPRESSO input file for a PBE0(0.25) calculation on the Si-Ca interface model
55.2 KiB Coordinates of various interface models (pure Si-Ca, pure Si-F, and intermediate bonding patterns)
36.8 KiB ABINIT input file for Si bulk calculations (PBE0, HSE, G0W0, QSGW etc. can be selected through the parameter 'jdtset')
28.0 KiB ABINIT input file for CaF2 bulk calculations (PBE0, HSE, G0W0, QSGW etc. can be selected through the parameter 'jdtset')


Files and data are licensed under the terms of the following license: Creative Commons Attribution 4.0 International.
Metadata, except for email addresses, are licensed under the Creative Commons Attribution Share-Alike 4.0 International license.


advanced electronic-structure calculations density functional theory hybrid functional GW method CaF2/Si interface band alignment narrow band gap system wide band gap system epitaxial growth SNSF EPFL

Version history:

2020.74 (version v1) [This version] Jul 13, 2020 DOI10.24435/materialscloud:m4-by