Jarek Dabrowski^1*

1 1IHP – Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany

* Corresponding authors emails: dabrowski@ihp-microelectronics.com

DOI10.24435/materialscloud:eq-s8 [version v1]

Publication date: Apr 23, 2025

How to cite this record

Jarek Dabrowski, Ge(110) c(8×10) reconstructions stabilized by vibrations, Materials Cloud Archive 2025.64 (2025), https://doi.org/10.24435/materialscloud:eq-s8

Description

Determining the atomic structure of a surface is essential for reliable simulations and in-depth exploration of chemical and atomic-scale physical processes. Using Ge(110) c(8×10) as a case study, this work employs Density Functional Theory (DFT) calculations to examine the role of vibrational entropy in surface reconstruction stability. The Ge(110) c(8×10) unit cell consists of interstitial-based pentamers (Universal Building Block model, UBB) interspersed with regions appearing in STM images as unreconstructed. DFT calculations predict that adding more pentamers lowers the surface energy, contradicting experimental findings. This discrepancy is resolved when vibrational entropy is accounted for and sur-face divacancies are introduced in addition to the UBB pentamers. These divacancies are similar to those proposed earlier in the Tetramer-Heptagonal and Tetragonal Ring (THTR) reconstruction model. The nearest neighbors of the vacancy sites are rebonded as on monatomic step edges. The differences in the vibrational entropy contributed by pentamers, divacancies, and unreconstructed surface stabilize Ge(110) c(8×10) reconstructions with the pentamer density observed experimentally. The presence of divacancies is conceptually consistent with the presence of monatomic steps in Ge(110) “16×2”, the most stable reconstruction of this surface.

Materials Cloud sections using this data

Files

File name	Size	Description
1_upf_pseudopotential_files.zip MD5md5:85fd321716c7e0b17bc6d62dd40a39a0	418.7 KiB	ZIP with pseudopotential files in UPF format (2 files).
2_cif_files_converged.zip MD5md5:8b3e7722992b8654f66d58794f6a0c1e	266.2 KiB	ZIP with atomic structures in CIF format (22 files). Accuracy level: converged (see the reference). Jmol script embedded in CIF will color-code various surface reconstruction elements (pentamers, zigzags, adatoms, vacancy sites).
3_cif_files_structure_scan_accuracy.zip MD5md5:48be4ddfcf48f0c4e29e692b9850b3c8	7.3 MiB	ZIP with atomic structures in CIF format (756 files). Accuracy level: structure scan (see the reference). For some files, Jmol script embedded in CIF will color-code surface pentamers and Ge(110) zigzags.

License

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.

External references

Keywords

Ge(110) surface reconstruction DFT PBE RVV10