1
|
Effect of Nitrogen Doping on the Crystallization Kinetics of Ge 2Sb 2Te 5. NANOMATERIALS 2021; 11:nano11071729. [PMID: 34209198 PMCID: PMC8308197 DOI: 10.3390/nano11071729] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 11/17/2022]
Abstract
Among the phase change materials, Ge2Sb2Te5 (GST-225) is the most studied and is already integrated into many devices. N doping is known to significantly improve some key characteristics such as the thermal stability of materials and the resistance drift of devices. However, the origin, at the atomic scale, of these alterations is rather elusive. The most important issue is to understand how N doping affects the crystallization characteristics, mechanisms and kinetics, of GST-225. Here, we report the results of a combination of in situ and ex situ transmission electron microscopy (TEM) investigations carried out on specifically designed samples to evidence the influence of N concentration on the crystallization kinetics and resulting morphology of the alloy. Beyond the known shift of the crystallization temperature and the observation of smaller grains, we show that N renders the crystallization process more "nucleation dominated" and ascribe this characteristic to the increased viscosity of the amorphous state. This increased viscosity is linked to the mechanical rigidity and the reduced diffusivity resulting from the formation of Ge-N bonds in the amorphous phase. During thermal annealing, N hampers the coalescence of the crystalline grains and the cubic to hexagonal transition. Making use of AbStrain, a recently invented TEM-based technique, we evidence that the nanocrystals formed from the crystallization of N-doped amorphous GST-225 are under tension, which suggests that N is inserted in the lattice and explains why it is not found at grain boundaries. Globally, all these results demonstrate that the origin of the effect of N on the crystallization of GST-225 is not attributed to the formation of a secondary phase such as a nitride, but to the ability of N to bind to Ge in the amorphous and crystalline phases and to unbind and rebind with Ge along the diffusion path of this atomic species during annealing.
Collapse
|
2
|
Kühne TD, Iannuzzi M, Del Ben M, Rybkin VV, Seewald P, Stein F, Laino T, Khaliullin RZ, Schütt O, Schiffmann F, Golze D, Wilhelm J, Chulkov S, Bani-Hashemian MH, Weber V, Borštnik U, Taillefumier M, Jakobovits AS, Lazzaro A, Pabst H, Müller T, Schade R, Guidon M, Andermatt S, Holmberg N, Schenter GK, Hehn A, Bussy A, Belleflamme F, Tabacchi G, Glöß A, Lass M, Bethune I, Mundy CJ, Plessl C, Watkins M, VandeVondele J, Krack M, Hutter J. CP2K: An electronic structure and molecular dynamics software package - Quickstep: Efficient and accurate electronic structure calculations. J Chem Phys 2020; 152:194103. [PMID: 33687235 DOI: 10.1063/5.0007045] [Citation(s) in RCA: 884] [Impact Index Per Article: 221.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
CP2K is an open source electronic structure and molecular dynamics software package to perform atomistic simulations of solid-state, liquid, molecular, and biological systems. It is especially aimed at massively parallel and linear-scaling electronic structure methods and state-of-the-art ab initio molecular dynamics simulations. Excellent performance for electronic structure calculations is achieved using novel algorithms implemented for modern high-performance computing systems. This review revisits the main capabilities of CP2K to perform efficient and accurate electronic structure simulations. The emphasis is put on density functional theory and multiple post-Hartree-Fock methods using the Gaussian and plane wave approach and its augmented all-electron extension.
Collapse
Affiliation(s)
- Thomas D Kühne
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
| | - Marcella Iannuzzi
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Mauro Del Ben
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Vladimir V Rybkin
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Patrick Seewald
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Frederick Stein
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Teodoro Laino
- IBM Research Europe, CH-8803 Rüschlikon, Switzerland
| | - Rustam Z Khaliullin
- Department of Chemistry, McGill University, CH-801 Sherbrooke St. West, Montreal, Quebec H3A 0B8, Canada
| | - Ole Schütt
- Department of Materials, ETH Zürich, CH-8092 Zürich, Switzerland
| | | | - Dorothea Golze
- Department of Applied Physics, Aalto University, Otakaari 1, FI-02150 Espoo, Finland
| | - Jan Wilhelm
- Institute of Theoretical Physics, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Sergey Chulkov
- School of Mathematics and Physics, University of Lincoln, Brayford Pool, Lincoln, United Kingdom
| | | | - Valéry Weber
- IBM Research Europe, CH-8803 Rüschlikon, Switzerland
| | | | | | | | | | - Hans Pabst
- Intel Extreme Computing, Software and Systems, Zürich, Switzerland
| | - Tiziano Müller
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Robert Schade
- Department of Computer Science and Paderborn Center for Parallel Computing, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
| | - Manuel Guidon
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Samuel Andermatt
- Integrated Systems Laboratory, ETH Zürich, CH-8092 Zürich, Switzerland
| | - Nico Holmberg
- Department of Chemistry and Materials Science, Aalto University, P.O. Box 16100, 00076 Aalto, Finland
| | - Gregory K Schenter
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | - Anna Hehn
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Augustin Bussy
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Fabian Belleflamme
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Gloria Tabacchi
- Department of Science and High Technology, University of Insubria and INSTM, via Valleggio 9, I-22100 Como, Italy
| | - Andreas Glöß
- BASF SE, Carl-Bosch-Straße 38, D-67056 Ludwigshafen am Rhein, Germany
| | - Michael Lass
- Department of Computer Science and Paderborn Center for Parallel Computing, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
| | - Iain Bethune
- Hartree Centre, Science and Technology Facilities Council, Sci-Tech Daresbury, Warrington WA4 4AD, United Kingdom
| | - Christopher J Mundy
- Physical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA
| | - Christian Plessl
- Department of Computer Science and Paderborn Center for Parallel Computing, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany
| | - Matt Watkins
- School of Mathematics and Physics, University of Lincoln, Brayford Pool, Lincoln, United Kingdom
| | - Joost VandeVondele
- Swiss National Supercomputing Centre (CSCS), ETH Zürich, Zürich, Switzerland
| | - Matthias Krack
- Laboratory for Scientific Computing and Modelling, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Jürg Hutter
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| |
Collapse
|
3
|
Gabardi S, Caravati S, Los JH, Kühne TD, Bernasconi M. Influence of the exchange and correlation functional on the structure of amorphous InSb and In3SbTe2 compounds. J Chem Phys 2016; 144:204508. [DOI: 10.1063/1.4950817] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Silvia Gabardi
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy
| | - Sebastiano Caravati
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy
| | - Jan H. Los
- Institute of Physical Chemistry and Center for Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 7, D-55128 Mainz, Germany
| | - Thomas D. Kühne
- Institute of Physical Chemistry and Center for Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 7, D-55128 Mainz, Germany
| | - Marco Bernasconi
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy
| |
Collapse
|