EHPRG: The European High Pressure Research Group

## Welcome

Welcome to the official website of the European High Pressure Research Group (EHPRG).

EHPRG is non-profitable academic association established in 1963 which is devoted to science and technology of matter under high pressure. It organizes an annual meeting which brings together hundreds of scientists of various fields, mainly physics, chemistry, Earth and planetary sciences, bio- and food science and technology.

The reasonable size of the group, low conference fees, and a friendly relationship between the attendants have made EHPRG meetings a major event in the European high-pressure community for more than half a century.

## Upcoming EHPRG Meeting

The 57th European High Pressure Research Group Meeting on High Pressure Science and Technology (EHPRG-2019) will be held in Prague, Czech Republic, from 1st to 6th September 2019. The 57th EHPRG Meeting will be chaired by Jiří Prchal (Charles University, Prague, Czech Republic).

Selection of high-pressure related titles from top scientific journals.

Snailfish is first animal from extreme ocean depths to get genome sequenced
by Erin I. Garcia de Jesus

Snailfish is first animal from extreme ocean depths to get genome sequenced

Snailfish is first animal from extreme ocean depths to get genome sequenced, Published online: 15 April 2019; doi:10.1038/d41586-019-01158-x

Gene sequence from fish living in the Mariana Trench reveals clues to living life under pressure.
15 Apr 2019 at 12:00am
Theoretical equations of state for a charged fluid
by X. Sánchez-Monroy
The Journal of Chemical Physics, Volume 150, Issue 14, April 2019.
In this article, we present a molecular thermodynamic study of a system of N particles contained within a volume V and interacting via a hard-core pair potential with an attractive interaction according to the Wolf model for charged systems. This variable-range potential is characterized by three parameters: the repulsive hard-core diameter σ, the energy-well depth ϵ, and the inverse range α; a fourth parameter of the model is a cut-off distance xc that depends on α according to the relation xc = 2/α. Two equations of state (EOSs) are presented and derived from thermodynamic perturbation theory and Monte Carlo (MC) simulation data. The first EOS is given by the standard Zwanzig’s high-temperature expansion of the Helmholtz free energy, where the first three perturbation terms a1, a2, and a3 were obtained from MC simulations in the canonical ensemble (NVT) and parameterized as functions of α and the reduced density of particles ρ* = Nσ3/V. The second EOS was obtained from the discrete perturbation theory applied to a discrete representation of the Wolf potential. Results for pressures, internal energies, and isochoric heat capacities are compared to the MC computer simulation data of the Wolf system, including vapor-liquid coexistence curves, for different values of α. Overall, both EOSs give a very good representation of the thermodynamic properties of the Wolf fluid when 0.3 ≤ α ≤ 1.0 and 0.05 ≤ ρ* ≤ 0.8. Since the Yukawa fluid can reproduce information of screened ionic interactions, we discuss the equivalence between the Wolf and Yukawa fluids in the context of equivalent systems in liquid theory.
10 Apr 2019 at 10:13am
Molecular dynamics simulations of nano-confined methanol and methanol-water mixtures between infinite graphite plates: Structure and dynamics
The Journal of Chemical Physics, Volume 150, Issue 14, April 2019.
Molecular dynamics simulations are used to investigate microscopic structures and dynamics of methanol and methanol-water binary mixture films confined between hydrophobic infinite parallel graphite plate slits with widths, H, in the range of 7–20 Å at 300 K. The initial geometric densities of the liquids were chosen to be the same as bulk methanol at the same temperature. For the two narrowest slit widths, two smaller initial densities were also considered. For the nano-confined system with H = 7 Å and high pressure, a solid-like hexagonal arrangement of methanol molecules arranged perpendicular to the plates is observed which reflects the closest packing of the molecules and partially mirrors the structure of the underlying graphite structure. At lower pressures and for larger slit widths, in the contact layer, the methanol molecules prefer having the C–O bond oriented parallel to the walls. Layered structures of methanol parallel to the wall were observed, with contact layers and additional numbers of central layers depending on the particular slit width. For methanol–water mixtures, simulations of solutions with different composition were performed between infinite graphite slits with H = 10 and 20 Å at 300 K. For the nanoslit with H = 10 Å, in the solution mixtures, three layers of molecules form, but for all mole fractions of methanol, methanol molecules are excluded from the central fluid layer. In the nanopore with H = 20 Å, more than three fluid layers are formed and methanol concentrations are enhanced near the confining plates walls compared to the average solution stoichiometry. The self-diffusion coefficients of methanol and water molecules in the solution show strong dependence on the solution concentration. The solution mole fractions with minimal diffusivity are the same in confined and non-confined bulk methanol-water mixtures.
11 Apr 2019 at 10:42am
Pressure-Induced Phase Transitions in Germanium Telluride: Raman Signatures of Anharmonicity and Oxidation
by Amit Pawbake, Christophe Bellin, Lorenzo Paulatto, Keevin Béneut, Johan Biscaras, Chandrabhas Narayana, Dattatray J. Late, and Abhay Shukla
Author(s): Amit Pawbake, Christophe Bellin, Lorenzo Paulatto, Keevin Béneut, Johan Biscaras, Chandrabhas Narayana, Dattatray J. Late, and Abhay Shukla

Pressure-induced phase transitions in GeTe, a prototype phase change material, have been studied to date with diffraction which is not sensitive to anharmonicity-induced dynamical effects. GeTe is also prone to surface oxidation which may compromise surface sensitive measurements. These factors coul...

[Phys. Rev. Lett. 122, 145701] Published Tue Apr 09, 2019
9 Apr 2019 at 12:00pm
Persistent Octahedral Coordination in Amorphous ${\mathrm{GeO}}_{2}$ Up to 100 GPa by $\mathrm{K}{β}^{′′}$ X-Ray Emission Spectroscopy
by G. Spiekermann, M. Harder, K. Gilmore, P. Zalden, Ch. J. Sahle, S. Petitgirard, M. Wilke, N. Biedermann, C. Weis, W. Morgenroth, J. S. Tse, E. Kulik, N. Nishiyama, H. Yavaş, and C. Sternemann
Author(s): G. Spiekermann, M. Harder, K. Gilmore, P. Zalden, Ch. J. Sahle, S. Petitgirard, M. Wilke, N. Biedermann, C. Weis, W. Morgenroth, J. S. Tse, E. Kulik, N. Nishiyama, H. Yavaş, and C. Sternemann

X-ray emission spectra reveal that under pressure conditions of Earth’s lower mantle, the compaction mechanism in amorphous germanium dioxide on the atomic scale is similar to that of its crystalline form.

[Phys. Rev. X 9, 011025] Published Wed Feb 06, 2019
6 Feb 2019 at 11:00am
Multisite Exchange-Enhanced Barocaloric Response in ${\mathrm{Mn}}_{3}\mathrm{NiN}$
by David Boldrin, Eduardo Mendive-Tapia, Jan Zemen, Julie B. Staunton, Thomas Hansen, Araceli Aznar, Josep-Lluís Tamarit, Maria Barrio, Pol Lloveras, Jiyeob Kim, Xavier Moya, and Lesley F. Cohen
Author(s): David Boldrin, Eduardo Mendive-Tapia, Jan Zemen, Julie B. Staunton, Thomas Hansen, Araceli Aznar, Josep-Lluís Tamarit, Maria Barrio, Pol Lloveras, Jiyeob Kim, Xavier Moya, and Lesley F. Cohen

Experiments reveal that Mn3NiN has enormous ability to control heat flow when subjected to mechanical pressure, establishing the family of Mn-antiperovskite materials as promising tools for energy-efficient refrigeration.

[Phys. Rev. X 8, 041035] Published Wed Nov 28, 2018
28 Nov 2018 at 11:00am
Solids, liquids, and gases under high pressure
by Ho-Kwang Mao, Xiao-Jia Chen, Yang Ding, Bing Li, and Lin Wang
Author(s): Ho-Kwang Mao, Xiao-Jia Chen, Yang Ding, Bing Li, and Lin Wang

The effect of adding high pressure as a control parameter in solids, liquids, and gases expands opportunities to observe unexpected novel phenomena and understand matter in extreme environments. This review on high pressure science highlights subjects ranging from quantum criticality to Earth science. State-of-the-art experimental methods at megabar pressures are also discussed. The proliferation of pressure-induced phases illustrate promising new directions for this field of research.

[Rev. Mod. Phys. 90, 015007] Published Tue Mar 20, 2018
20 Mar 2018 at 11:00am
Colloquium: High pressure and road to room temperature superconductivity
by Lev P. Gor’kov and Vladimir Z. Kresin
Author(s): Lev P. Gor’kov and Vladimir Z. Kresin

Even after three decades of development, high-temperature superconductivity remains one of the most challenging theoretical and experimental areas in condensed matter physics. In this Colloquium some new discoveries in this area are reviewed and possible routes toward much higher transition temperatures are analyzed.

[Rev. Mod. Phys. 90, 011001] Published Tue Jan 09, 2018
9 Jan 2018 at 11:00am
Equations of state for supernovae and compact stars
by M. Oertel, M. Hempel, T. Klähn, and S. Typel
Author(s): M. Oertel, M. Hempel, T. Klähn, and S. Typel

What are the thermodynamic properties of matter at extreme densities, even exceeding nuclear matter density severely? How can we describe the composition of matter for such conditions, the resulting pressure, and the maximum mass of cold neutron stars? How is this affected by finite temperatures, as they occur in core collapse supernovae and in compact star mergers? This review addresses these points within the framework of constraints from experiments as well as astronomical observations.

[Rev. Mod. Phys. 89, 015007] Published Wed Mar 15, 2017
15 Mar 2017 at 11:00am
Ambipolar suppression of superconductivity by ionic gating in optimally doped ${\mathrm{BaFe}}_{2}{(\mathrm{As},\mathrm{P})}_{2}$ ultrathin films
by Erik Piatti, Takafumi Hatano, Dario Daghero, Francesco Galanti, Claudio Gerbaldi, Salvatore Guastella, Chiara Portesi, Ibuki Nakamura, Ryosuke Fujimoto, Kazumasa Iida, Hiroshi Ikuta, and Renato S. Gonnelli
Author(s): Erik Piatti, Takafumi Hatano, Dario Daghero, Francesco Galanti, Claudio Gerbaldi, Salvatore Guastella, Chiara Portesi, Ibuki Nakamura, Ryosuke Fujimoto, Kazumasa Iida, Hiroshi Ikuta, and Renato S. Gonnelli

Superconductivity (SC) in the Ba-122 family of iron-based compounds can be controlled by aliovalent or isovalent substitutions, applied external pressure, and strain, the combined effects of which are sometimes studied within the same sample. Most often, the result is limited to a shift of the SC do...

[Phys. Rev. Materials 3, 044801] Published Mon Apr 15, 2019
15 Apr 2019 at 12:00pm
Pressure tuning of the electrical transport properties in the Weyl semimetal TaP
by M. Besser, R. D. dos Reis, F.-R. Fan, M. O. Ajeesh, Y. Sun, M. Schmidt, C. Felser, and M. Nicklas
Author(s): M. Besser, R. D. dos Reis, F.-R. Fan, M. O. Ajeesh, Y. Sun, M. Schmidt, C. Felser, and M. Nicklas

We investigated the pressure evolution of the electrical transport in the almost compensated Weyl semimetal TaP. In addition, we obtained information on the modifications of the Fermi-surface topology with pressure from the analysis of pronounced Shubnikov–de Haas (SdH) quantum oscillations present ...

[Phys. Rev. Materials 3, 044201] Published Wed Apr 10, 2019
10 Apr 2019 at 12:00pm
Probing the quantum phase transition in Mott insulator ${\mathrm{BaCoS}}_{2}$ tuned by pressure and Ni substitution
by Z. Guguchia, B. A. Frandsen, D. Santos-Cottin, S. C. Cheung, Z. Gong, Q. Sheng, K. Yamakawa, A. M. Hallas, M. N. Wilson, Y. Cai, J. Beare, R. Khasanov, R. De Renzi, G. M. Luke, S. Shamoto, A. Gauzzi, Y. Klein, and Y. J. Uemura
Author(s): Z. Guguchia, B. A. Frandsen, D. Santos-Cottin, S. C. Cheung, Z. Gong, Q. Sheng, K. Yamakawa, A. M. Hallas, M. N. Wilson, Y. Cai, J. Beare, R. Khasanov, R. De Renzi, G. M. Luke, S. Shamoto, A. Gauzzi, Y. Klein, and Y. J. Uemura

We present a muon spin relaxation study of the Mott transition in ${\mathrm{BaCoS}}_{2}$ using two independent control parameters: (i) pressure $p$ to tune the electronic bandwidth and (ii) Ni substitution $x$ on the Co site to tune the band filling. For both tuning parameters, the antiferromagnetic...

[Phys. Rev. Materials 3, 045001] Published Fri Apr 05, 2019
5 Apr 2019 at 12:00pm
Structural transition in cold-compressed glassy carbon
by Zhidan Zeng, Hongwei Sheng, Liuxiang Yang, Hongbo Lou, Lijie Tan, Vitali B. Prakapenka, Eran Greenberg, and Qiaoshi Zeng
Author(s): Zhidan Zeng, Hongwei Sheng, Liuxiang Yang, Hongbo Lou, Lijie Tan, Vitali B. Prakapenka, Eran Greenberg, and Qiaoshi Zeng

Glassy carbon (GC) distinguishes itself from other carbon materials by its unique atomic structure and properties. Cold-compressed GC gives rise to new physical properties; however, the atomistic mechanism for the transitions remains elusive. In this study, by combining in situ high-pressure x-ray d...

[Phys. Rev. Materials 3, 033608] Published Wed Mar 27, 2019
27 Mar 2019 at 11:00am
Angular dependence of the upper critical field in the high-pressure $1{T}^{′}$ phase of ${\mathrm{MoTe}}_{2}$
by Y. J. Hu, Yuk Tai Chan, Kwing To Lai, Kin On Ho, Xiaoyu Guo, Hai-Peng Sun, K. Y. Yip, Dickon H. L. Ng, Hai-Zhou Lu, and Swee K. Goh
Author(s): Y. J. Hu, Yuk Tai Chan, Kwing To Lai, Kin On Ho, Xiaoyu Guo, Hai-Peng Sun, K. Y. Yip, Dickon H. L. Ng, Hai-Zhou Lu, and Swee K. Goh

Superconductivity in the type-II Weyl semimetal candidate ${\mathrm{MoTe}}_{2}$ has attracted much attention due to the possible realization of topological superconductivity. Under applied pressure, the superconducting transition temperature is significantly enhanced, while the structural transition...

[Phys. Rev. Materials 3, 034201] Published Mon Mar 25, 2019
25 Mar 2019 at 11:00am
Controlling the interfacial conductance in ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ in ${90}^{∘}$ off-axis sputter deposition
by Chunhai Yin, Dileep Krishnan, Nicolas Gauquelin, Jo Verbeeck, and Jan Aarts
Author(s): Chunhai Yin, Dileep Krishnan, Nicolas Gauquelin, Jo Verbeeck, and Jan Aarts

We report on the fabrication of conducting interfaces between ${\mathrm{LaAlO}}_{3}$ and ${\mathrm{SrTiO}}_{3}$ by ${90}^{∘}$ off-axis sputtering in an Ar atmosphere. At a growth pressure of 0.04 mbar the interface is metallic, with a carrier density of the order of $1×{10}^{13}\phantom{\rule{4pt}{0... [Phys. Rev. Materials 3, 034002] Published Tue Mar 12, 2019 12 Mar 2019 at 11:00am Giant power output in lead-free ferroelectrics by shock-induced phase transition by Zhipeng Gao, Wei Peng, Bin Chen, Simon A. T. Redfern, Ke Wang, Baojin Chu, Qiang He, Yi Sun, Xuefeng Chen, Hengchang Nie, Wen Deng, Lingkong Zhang, Hongliang He, Genshui Wang, and Xianlin Dong Author(s): Zhipeng Gao, Wei Peng, Bin Chen, Simon A. T. Redfern, Ke Wang, Baojin Chu, Qiang He, Yi Sun, Xuefeng Chen, Hengchang Nie, Wen Deng, Lingkong Zhang, Hongliang He, Genshui Wang, and Xianlin Dong The force-electric effect in ferroelectrics is characterized by the release of bound charge during pressure/shock-induced depolarization. In contrast to other electrical energy storage systems, the charge-storage/release by the force-electric effect of ferroelectrics is determined by polarization sw... [Phys. Rev. Materials 3, 035401] Published Mon Mar 11, 2019 11 Mar 2019 at 11:00am Superconductor-insulator transition driven by pressure-tuned intergrain coupling in nanodiamond films by Gufei Zhang, Yonghui Zhou, Svetlana Korneychuk, Tomas Samuely, Liwang Liu, Paul W. May, Zheng Xu, Oleksandr Onufriienko, Xuefeng Zhang, Johan Verbeeck, Peter Samuely, Victor V. Moshchalkov, Zhaorong Yang, and Horst-Günter Rubahn Author(s): Gufei Zhang, Yonghui Zhou, Svetlana Korneychuk, Tomas Samuely, Liwang Liu, Paul W. May, Zheng Xu, Oleksandr Onufriienko, Xuefeng Zhang, Johan Verbeeck, Peter Samuely, Victor V. Moshchalkov, Zhaorong Yang, and Horst-Günter Rubahn We report on the pressure-driven superconductor-insulator transition in heavily boron-doped nanodiamond films. By systematically increasing the pressure, we suppress the Josephson coupling between the superconducting nanodiamond grains. The diminished intergrain coupling gives rise to an overall ins... [Phys. Rev. Materials 3, 034801] Published Tue Mar 05, 2019 5 Mar 2019 at 11:00am Structural, electronic, and dynamical properties of the tetragonal and collapsed tetragonal phases of${\mathrm{KFe}}_{2}{\mathrm{As}}_{2}$by Andrzej Ptok, Małgorzata Sternik, Konrad Jerzy Kapcia, and Przemysław Piekarz Author(s): Andrzej Ptok, Małgorzata Sternik, Konrad Jerzy Kapcia, and Przemysław Piekarz Compounds with a tetragonal${\mathrm{ThCr}}_{2}{\mathrm{Si}}_{2}$-type structure are characterized by the possibility of the isostructural phase transition from the tetragonal phase to the collapsed tetragonal phase induced by the external pressure. An example of a compound with such a phase transi... [Phys. Rev. B 99, 134103] Published Mon Apr 15, 2019 15 Apr 2019 at 12:00pm Light irradiation induced brittle-to-ductile and ductile-to-brittle transition in inorganic semiconductors by Hongwei Wang, Sergey I. Morozov, William A. Goddard, III, and Qi An Author(s): Hongwei Wang, Sergey I. Morozov, William A. Goddard, III, and Qi An The intrinsic brittleness of inorganic semiconductors prevents them from extended engineering applications under extreme conditions of high temperature and pressure, making it essential to improve their ductility. Here, we applied the constrained density functional theory to examine the relationship... [Phys. Rev. B 99, 161202(R)] Published Fri Apr 12, 2019 12 Apr 2019 at 12:00pm Pressure-temperature phase diagram of the${\mathrm{EuRbFe}}_{4}{\mathrm{As}}_{4}$superconductor by Li Xiang, Sergey L. Bud'ko, Jin-Ke Bao, Duck Young Chung, Mercouri G. Kanatzidis, and Paul C. Canfield Author(s): Li Xiang, Sergey L. Bud'ko, Jin-Ke Bao, Duck Young Chung, Mercouri G. Kanatzidis, and Paul C. Canfield The pressure dependencies of the magnetic and superconducting transitions, as well as that of the superconducting upper critical field, are reported for single crystalline${\mathrm{EuRbFe}}_{4}{\mathrm{As}}_{4}\$. Resistance measurements were performed under hydrostatic pressures up to 6.21 GPa and ...

[Phys. Rev. B 99, 144509] Published Thu Apr 11, 2019
11 Apr 2019 at 12:00pm