Structural phase transitions of sodium nitride at high pressure

Vajenine, Grigori V.; Wang, X.; Efthimiopoulos, Ilias; Karmakar, S.; Syassen, K.; Hanfland, Michael

doi:10.1103/physrevb.79.224107

Cited by 33 publications

(28 citation statements)

References 36 publications

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“…Sodium nitride Na 3 N. Another deceptively simple chemical system where a successful synthesis followed the prediction is Na 3 N. 8 In several studies Schö n et al, 2000Schö n et al, , 2001b, the enthalpy landscapes of all alkali nitrides M 3 N (M = Li, Na, K, Rb, Cs) were explored with simulated annealing and the threshold algorithm for a wide range of pressures. Furthermore, at intermediary pressures another modification exhibiting the YF 3 type was observed (Vajenine et al, 2008(Vajenine et al, , 2009) that resembles several structures found as local minima on the enthalpy landscapes of the alkali nitrides. Fig.…”

Section: Theoretical Applicationsmentioning

confidence: 54%

“…5.1.2. Experimentally, the ReO 3 type (Fischer & Jansen, 2002b), the Li 3 N, the Li 3 P and the Li 3 Bi structure types (Vajenine et al, 2008(Vajenine et al, , 2009) have all been synthesized, the latter three using high-pressure experiments starting from the ReO 3 type. This resulted in a large number of structure candidates, including, for example, the Li 3 N, the Li 3 P, the Li 3 Bi, the AuCu 3 , the Al 3 Ti, the ReO 3 and the UO 3 structure types, plus many previously unknown structure types.…”

Section: Theoretical Applicationsmentioning

confidence: 99%

“…I-Na 3 N corresponds to a strongly distorted Li 3 Bi structure type with 12(+2)-fold coordination of the nitrogen atoms by sodium atoms. Experimentally, the ReO 3 type (Fischer & Jansen, 2002b), the Li 3 N, the Li 3 P and the Li 3 Bi structure types (Vajenine et al, 2008(Vajenine et al, , 2009) have all been synthesized, the latter three using high-pressure experiments starting from the ReO 3 type. Furthermore, at intermediary pressures another modification exhibiting the YF 3 type was observed (Vajenine et al, 2008(Vajenine et al, , 2009) that resembles several structures found as local minima on the enthalpy landscapes of the alkali nitrides.…”

Section: Theoretical Applicationsmentioning

confidence: 99%

See 2 more Smart Citations

Addressing chemical diversity by employing the energy landscape concept

Jansen¹,

Doll²,

Schön³

2010

Acta Cryst Sect A

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Exploring the structural diversity of a chemical system rests on three pillars. First, there is the global exploration of its energy landscape that allows one to predict which crystalline modifications can exist in a chemical system at a given temperature and pressure. Next, there is the development of new synthesis methods in solid-state chemistry, which require only very low activation energies such that even metastable modifications corresponding, for example, to minima on the landscape surrounded by low barriers can be realized. Finally, there is the theoretical design of optimal synthesis routes, again based on the study of the system's energy landscape. In this paper the energy landscape approach to the prediction of stable and metastable compounds as a function of temperature and pressure is presented, with a particular focus on possible phase transitions. Furthermore, several examples are presented, where such predicted compounds were subsequently successfully synthesized, often employing a newly developed synthesis method, low-temperature atom-beam deposition.

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Section: Theoretical Applicationsmentioning

confidence: 54%

Section: Theoretical Applicationsmentioning

confidence: 99%

Section: Theoretical Applicationsmentioning

confidence: 99%

See 1 more Smart Citation

Addressing chemical diversity by employing the energy landscape concept

Jansen¹,

Doll²,

Schön³

2010

Acta Cryst Sect A

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“…8) have recently been realized [83]. This impressively documents the strength of our new rational way for solid-state synthesis, and this result has attracted a lot of interest, which in part arose because of generations of solid-state chemists having tried in vain to synthesize Na 3 N.…”

Section: Experimental Verificationsmentioning

confidence: 90%

The energy landscape concept and its implications for synthesis planning

Jansen

2014

Pure and Applied Chemistry

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Synthesis of novel solids, in a chemical sense, is one of the spearheads of innovation in materials research. However, such an undertaking is substantially impaired by lack of control and predictability. We present a concept that points the way towards rational planning of syntheses in solid state and materials chemistry. The foundation of our approach is the representation of the whole material world, i.e., the known and not-yet-known chemical compounds, on an energy landscape, which implies information about the free energies of these configurations. From this it follows at once that all chemical compounds capable of existence (both thermodynamically stable and metastable ones) are already present in virtuo in this landscape. For the first step of synthesis planning, i.e., the identification of candidates that are capable of existence, we computationally search the respective potential energy landscapes for (meta)stable structure candidates. Recently we have extended our techniques to finite temperatures and pressures and calculated phase diagrams, including metastable manifestations of matter, without resorting to any experimental pre-information. The conception developed is physically consistent, and its feasibility has been proven. Applying appropriate experimental tools has enabled us to realize, e.g., elusive Na 3 N, including almost all of its predicted polymorphs, many years after the predictions were published.

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“…Since the computational efforts to be made at exploring configuration spaces of significant size are huge, in the beginning, we based the total energy calculations on computationally "cheap" empirical two-body potentials. [2a-d] In spite of this approximation, the results have been quite promising, and the feasibility of the concept has been proven convincingly and validated experimentally at the example of the alkali metal nitrides [13][14][15] and the lithium halides. [16,17] However, the two-body potentials used, consisting of a Coulombic and a Lennard-Jones term, give predominantly ionic structures and are not suitable to address, for example, configurations containing homoatomic bonds.…”

mentioning

confidence: 98%

Ab Initio Energy Landscape of GeF₂: A System Featuring Lone Pair Structure Candidates

Doll¹,

Jansen²

2011

Angew Chem Int Ed

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Dedicated to Professor Hansgeorg Schnöckel on the occasion of his 70th birthdayEach already known chemical configuration, as well as those that are stable but are still waiting to be experimentally discovered, corresponds to a minimum on the hyperspace of potential energy associated with the (chemical) configuration space. At finite temperatures, the configurations around such minimum structures are populated, constituting a "locally ergodic" region, corresponding to a macroscopic thermodynamic state, which can be addressed by the thermodynamic state functions G, H, and S. Since the structure of the potential energy landscape, and the locally ergodic regions present, are determined by natural laws, all chemical compounds and their structures are also predetermined. It follows that neither the composition, nor the structure, nor the properties of a specific chemical configuration is subject to external intervention, for example, by the synthetic chemist. [1] Projecting the whole wealth of existing and not yet realized chemical configurations onto the related landscape of potential energy at 0 K, and the ergodic states of matter evolving at finite temperatures, is the foundation of our concept for targeted materials and solid-state syntheses.[2] In this picture, the first step of synthesis planning, namely predicting stable configurations that can serve as targets for synthesis, imposes the task of analyzing the energy landscape for local minima. Since even subsections of such a landscape cannot be computed by solving the Schrödinger equation for the ensembles of atoms to be realistically involved, one has to resort to the tools developed for the exploration of multiminima landscapes, for example, by scanning it using random walks. We have employed simulated annealing, in combination with steps according to the Monte Carlo method, using the total energy as the only cost function, and number and type of atoms, their positional vectors, and, most importantly, the lattice basis as parameters to be varied (move classes). [2] Meanwhile, several related approaches for the prediction of structures by global optimization have been introduced, among them molecular dynamics in various variants (e.g. metadynamics, [3] or a combination of molecular dynamics and path sampling [4] ), genetic (evolutionary) algorithms, [5][6][7][8] or simply performing a local optimization, starting from random structures.[9] For overviews on structure prediction and energy landscapes, see, for example, references [2,[10][11][12].The shape of the energy landscape, as imaged by such a computational process, depends crucially on the quality and kind of the total energy calculations and to a lesser extent on the move classes applied, and will more or less deviate from the "true" landscape. Since the computational efforts to be made at exploring configuration spaces of significant size are huge, in the beginning, we based the total energy calculations on computationally "cheap" empirical two-body potentials. [2a-d] In spite of this approximation, th...

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Structural phase transitions of sodium nitride at high pressure

Cited by 33 publications

References 36 publications

Addressing chemical diversity by employing the energy landscape concept

Addressing chemical diversity by employing the energy landscape concept

The energy landscape concept and its implications for synthesis planning

Ab Initio Energy Landscape of GeF₂: A System Featuring Lone Pair Structure Candidates

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Structural phase transitions of sodium nitride at high pressure

Cited by 33 publications

References 36 publications

Addressing chemical diversity by employing the energy landscape concept

Addressing chemical diversity by employing the energy landscape concept

The energy landscape concept and its implications for synthesis planning

Ab Initio Energy Landscape of GeF2: A System Featuring Lone Pair Structure Candidates

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Ab Initio Energy Landscape of GeF₂: A System Featuring Lone Pair Structure Candidates