Katerina P. Hilleke

Bio: Katerina P. Hilleke is an academic researcher from University at Buffalo. The author has contributed to research in topics: Ternary operation & Crystal structure prediction. The author has an hindex of 3, co-authored 7 publications receiving 22 citations.

The XtalOpt Evolutionary Algorithm for Crystal Structure Prediction

Abstract: Significant progress has been made in the field of a priori crystal structure prediction, with a number of recent remarkable success stories. Herein, we briefly outline the methods that have been d...

Tuning Chemical Precompression: Theoretical Design and Crystal Chemistry of Novel Hydrides in the Quest for Warm and Light Superconductivity at Ambient Pressures.

Abstract: Over the past decade, a combination of crystal structure prediction techniques and experimental synthetic work has thoroughly explored the phase diagrams of binary hydrides under pressure. The fruitfulness of this dual approach is demonstrated in the recent identification of several superconducting hydrides with $T_c$s approaching room temperature. We start with an overview of the computational procedures for predicting stable structures and estimating their propensity for superconductivity. A survey of phases with high $T_c$ reveals some common structural features that appear conducive to the strong coupling of the electronic structure with atomic vibrations that leads to superconductivity. We discuss the stability and superconducting properties of phases containing two of these -- molecular H$_2$ units mixed with atomic H and hydrogenic clathrate-like cages -- as well as more unique motifs. Finally, we argue that ternary hydride phases, which are far less-explored, are a promising route to achieving simultaneously superconductivity at high temperatures and stability at low pressures. Several ternary hydrides arise from the addition of a third element to a known binary hydride structure through site mixing or onto a new site -- and several more are based on altogether new structural motifs.

Structural motifs and bonding in two families of boron structures predicted at megabar pressures

Abstract: The complex crystal chemistry of elemental boron has led to numerous proposed structures with distinctive motifs as well as contradictory findings. Herein, evolutionary structure searches performed at 100 GPa have uncovered a series of metastable phases of boron, and bonding analyses were carried out to elucidate their electronic structure. These polymorphs, dynamically stable at 100 GPa, were grouped into two families. The first was derived from the thermodynamic minimum at these conditions, $\ensuremath{\alpha}$-Ga, whereas channels comprised the second. Two additional intergrowth structures were uncovered, and it was shown they could be constructed by stacking layers of $\ensuremath{\alpha}$-Ga-like and channel-like allotropes on top of each other. A detailed bonding analysis revealed networks of four-center $\ensuremath{\sigma}$-bonding functions linked by two-center B-B bonds in the $\ensuremath{\alpha}$-Ga based structures, and networks that were largely composed of three-center $\ensuremath{\sigma}$-bonding functions in the channel-based structures. Seven of these high-pressure phases were found to be metastable at atmospheric conditions, and their Vickers hardnesses were estimated to be $\ensuremath{\approx}36$ GPa.

Pressure-Induced Superconductivity in the Wide-Band-GapSemiconductor Cu 2 Br 2 Se 6 with a RobustFramework

Abstract: We report pressure-induced superconductivity in a ternary and nonmagnetic Cu-containing semiconductor, Cu2Br2Se6, with a wide band gap of 1.89 eV, in which the Cu and Br atoms generate infinite 21 ...

RbB3Si3: An Alkali Metal Borosilicide that is Metastable and Superconducting at 1 atm

Abstract: The stability, electronic structure, and potential superconductivity in AB3Si3 (A = Na, K, Rb, and Cs) compounds that assume a clathrate-based sodalite structure whose framework consists of covalen...

Complex Hydrides for Hydrogen Storage

Abstract: Note: Times Cited: 875 Reference EPFL-ARTICLE-206025doi:10.1021/cr0501846View record in Web of Science URL: ://WOS:000249839900009 Record created on 2015-03-03, modified on 2017-05-12

The 2021 room-temperature superconductivity roadmap

Abstract: Even though superconductivity has been studied intensively for more than a century, the vast majority of superconductivity research today is carried out in nearly the same manner as decades ago. That is, each study tends to focus on only a single material or small subset of materials, and discoveries are made more or less serendipitously. Recent increases in computing power, novel machine learning algorithms, and improved experimental capabilities offer new opportunities to revolutionize superconductor discovery. These will enable the rapid prediction of structures and properties of novel materials in an automated, high-throughput fashion and the efficient experimental testing of these predictions. Here, we review efforts to use machine learning to attain this goal.

The high-throughput highway to computational materials design: finding new magnets

Abstract: High-throughput computational materials design is an emerging area of materials science. By combining advanced thermodynamic and electronic-structure methods with intelligent data mining and database construction, and exploiting the power of current supercomputer architectures, scientists generate, manage and analyse enormous data repositories for the discovery of novel materials. In this Review we provide a current snapshot of this rapidly evolving field, and highlight the challenges and opportunities that lie ahead.

化学講話 ロアルド・ホフマン博士講演録 狭い空間で働く化学概念--The Chemical Imagination at Work in Very Tight Places

Abstract: Diamond-anvil-cell and shock-wave technologies now permit the study of matter under multimegabar pressure (that is, of several hundred GPa). The properties of matter in this pressure regime differ drastically from those known at 1 atm (about 10(5) Pa). Just how different chemistry is at high pressure and what role chemical intuition for bonding and structure can have in understanding matter at high pressure will be explored in this account. We will discuss in detail an overlapping hierarchy of responses to increased density: a) squeezing out van der Waals space (for molecular crystals); b) increasing coordination; c) decreasing the length of covalent bonds and the size of anions; and d) in an extreme regime, moving electrons off atoms and generating new modes of correlation. Examples of the startling chemistry and physics that emerge under such extreme conditions will alternate in this account with qualitative chemical ideas about the bonding involved.