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 high pressure meetings

The current COVID pandemic has led to the cancellation of numerous scientific conferences over the last year, including the 2020 GRC and GRS high-pressure conferences, and the combined AIRAPT/EHPRG-2021 conference that was to be held in Edinburgh this summer. The negative effects of this are being most keenly felt by younger researchers, who have missed golden opportunities to present both their work, and themselves, to the rest of the community.
This online conference aims to address this, by providing up to 360 20-minute oral presentations in which young and early career researchers in our field to present their research to the rest of our international community. Such researchers will be offered the great majority of these slots, complemented by some didactic talks from more established researchers and facility operators. Everyone in the high-pressure community is welcome to attend.
CESC-2021 will be chaired by Malcolm McMahon.

## Upcoming EHPRG Meeting

The Joint 28th AIRAPT and 60th EHPRG International Conference on High Pressure Science and Technology (AIRAPT-2021), originally scheduled for July 2021, has been postponed, and will be held in Edinburgh, UK, in 2023. Exact dates will be announced as soon as possible. AIRAPT-21 will be chaired by Malcolm McMahon (CSEC and University of Edinburgh, UK).
In spite of the Joint AIRAPT-EHPRG Conference, an online Conference on Science at Extreme Conditions will take place in 2021. This online event will have a special focus on young and early career researchers. This will NOT be an AIRAPT/EHPRG conference, but the organizers expect to be able to offer up to 360 slots for 20-minute, and 5-minute “lightning”, oral presentations, spread over 5 days, each of which will have two 2-hour time slots (11am-1pm and 3-5pm UK time), timed so as to provide “office hours” access to speakers from Asia/Europe and Americas/Europe, respectively. Each 2-hour time slot will host up to 6 parallel sessions. The great majority of the available slots for talks will be given to young researchers, complemented by some didactic presentations from more established researchers and facility providers. Everyone in the high-pressure community is welcome to attend.

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

Equation of state for confined fluids
by Vilde Bråten
The Journal of Chemical Physics, Volume 156, Issue 24, June 2022.
Fluids confined in small volumes behave differently than fluids in bulk systems. For bulk systems, a compact summary of the system’s thermodynamic properties is provided by equations of state. However, there is currently a lack of successful methods to predict the thermodynamic properties of confined fluids by use of equations of state, since their thermodynamic state depends on additional parameters introduced by the enclosing surface. In this work, we present a consistent thermodynamic framework that represents an equation of state for pure, confined fluids. The total system is decomposed into a bulk phase in equilibrium with a surface phase. The equation of state is based on an existing, accurate description of the bulk fluid and uses Gibbs’ framework for surface excess properties to consistently incorporate contributions from the surface. We apply the equation of state to a Lennard-Jones spline fluid confined by a spherical surface with a Weeks–Chandler–Andersen wall-potential. The pressure and internal energy predicted from the equation of state are in good agreement with the properties obtained directly from molecular dynamics simulations. We find that when the location of the dividing surface is chosen appropriately, the properties of highly curved surfaces can be predicted from those of a planar surface. The choice of the dividing surface affects the magnitude of the surface excess properties and its curvature dependence, but the properties of the total system remain unchanged. The framework can predict the properties of confined systems with a wide range of geometries, sizes, interparticle interactions, and wall–particle interactions, and it is independent of ensemble. A targeted area of use is the prediction of thermodynamic properties in porous media, for which a possible application of the framework is elaborated.
28 Jun 2022 at 11:50am
Mechanical feedback controls the emergence of dynamical memory in growing tissue monolayers
by Sumit Sinha
The Journal of Chemical Physics, Volume 156, Issue 24, June 2022.
The growth of a tissue, which depends on cell–cell interactions and biologically relevant processes such as cell division and apoptosis, is regulated by a mechanical feedback mechanism. We account for these effects in a minimal two-dimensional model in order to investigate the consequences of mechanical feedback, which is controlled by a critical pressure, pc. A cell can only grow and divide if its pressure, due to interaction with its neighbors, is less than pc. Because temperature is not a relevant variable, the cell dynamics is driven by self-generated active forces (SGAFs) that arise due to cell division. We show that even in the absence of intercellular interactions, cells undergo diffusive behavior. The SGAF-driven diffusion is indistinguishable from the well-known dynamics of a free Brownian particle at a fixed finite temperature. When intercellular interactions are taken into account, we find persistent temporal correlations in the force–force autocorrelation function (FAF) that extends over a timescale of several cell division times. The time-dependence of the FAF reveals memory effects, which increases as pc increases. The observed non-Markovian effects emerge due to the interplay of cell division and mechanical feedback and are inherently a non-equilibrium phenomenon.
22 Jun 2022 at 3:43am
Supertransport by Superclimbing Dislocations in $^{4}\mathrm{He}$: When All Dimensions Matter
by Anatoly B. Kuklov, Lode Pollet, Nikolay V. Prokof’ev, and Boris V. Svistunov
Author(s): Anatoly B. Kuklov, Lode Pollet, Nikolay V. Prokof’ev, and Boris V. Svistunov

The unique superflow-through-solid effect observed in solid $^{4}\mathrm{He}$ and attributed to the quasi-one-dimensional superfluidity along the dislocation cores exhibits two extraordinary features: (i) an exponentially strong suppression of the flow by a moderate increase in pressure and (ii) an …

[Phys. Rev. Lett. 128, 255301] Published Tue Jun 21, 2022
21 Jun 2022 at 12:00pm
Superconductivity of ${\mathrm{MoBe}}_{22}$ and ${\mathrm{WBe}}_{22}$ at ambient- and under applied-pressure conditions
by T. Shiroka, T. Shang, M. Juckel, M. Krnel, M. König, U. Burkhardt, P. Koželj, R. Gupta, Yu. Prots, and E. Svanidze
Author(s): T. Shiroka, T. Shang, M. Juckel, M. Krnel, M. König, U. Burkhardt, P. Koželj, R. Gupta, Yu. Prots, and E. Svanidze

${\mathrm{MoBe}}_{22}$ and ${\mathrm{WBe}}_{22}$ compounds belong to the binary $X{\mathrm{Be}}_{22}$ $(X=4d$ or 5$d$ metal) family of superconductors, whose critical temperature depends strongly on $X$. Despite the multiphase nature of these samples, it is possible to investigate the superconductin…

[Phys. Rev. Materials 6, 064804] Published Mon Jun 27, 2022
27 Jun 2022 at 12:00pm
Determination of indium melting curve at high pressure by picosecond acoustics
by Simon Ayrinhac, Michel Gauthier, Marc Morand, Yiuri Garino, Silvia Boccato, Frédéric Decremps, Paraskevas Parisiades, Philippe Rosier, Nicki C. Siersch, Abderraouf Seghour, and Daniele Antonangeli
Author(s): Simon Ayrinhac, Michel Gauthier, Marc Morand, Yiuri Garino, Silvia Boccato, Frédéric Decremps, Paraskevas Parisiades, Philippe Rosier, Nicki C. Siersch, Abderraouf Seghour, and Daniele Antonangeli

Picosecond acoustics combined with a diamond anvil cell is used to study liquid indium and to determine with high accuracy both the sound velocity and the melting curve over an extended pressure and temperature range. The sound velocities, determined by phonon surface imaging, complement previous in…

[Phys. Rev. Materials 6, 063403] Published Thu Jun 16, 2022
16 Jun 2022 at 12:00pm
Superconductivity in S-rich phases of lanthanum sulfide under high pressure
by Kun Gao, Wenwen Cui, Qinfang Wang, Jian Hao, Jingming Shi, Silvana Botti, Miguel A. L. Marques, and Yinwei Li
Author(s): Kun Gao, Wenwen Cui, Qinfang Wang, Jian Hao, Jingming Shi, Silvana Botti, Miguel A. L. Marques, and Yinwei Li

Pressure, a fundamental thermodynamic variable, enables phase transitions to exotic phases with unique physical properties, such as superconductivity. In this work we perform a complete study of crystal structures and relevant electronic properties of La–S crystalline systems in a pressure range of …

[Phys. Rev. Materials 6, 064801] Published Wed Jun 15, 2022
15 Jun 2022 at 12:00pm
Unusual magnetic and transport properties in ${\mathrm{HoMn}}_{6}{\mathrm{Sn}}_{6}$ kagome magnet
by Firoza Kabir, Randall Filippone, Gyanendra Dhakal, Y. Lee, Narayan Poudel, Jacob Casey, Anup Pradhan Sakhya, Sabin Regmi, Robert Smith, Pietro Manfrinetti, Liqin Ke, Krzysztof Gofryk, Madhab Neupane, and Arjun K. Pathak
Author(s): Firoza Kabir, Randall Filippone, Gyanendra Dhakal, Y. Lee, Narayan Poudel, Jacob Casey, Anup Pradhan Sakhya, Sabin Regmi, Robert Smith, Pietro Manfrinetti, Liqin Ke, Krzysztof Gofryk, Madhab Neupane, and Arjun K. Pathak

With intricate lattice structures, kagome materials are an excellent platform to study various fascinating topological quantum states. In particular, kagome materials, revealing large responses to external stimuli such as pressure or magnetic field, are subject to special investigation. Here we stud…

[Phys. Rev. Materials 6, 064404] Published Tue Jun 07, 2022
7 Jun 2022 at 12:00pm
Competing dynamical and lattice instabilities in ${R\mathrm{VO}}_{4}$ rare-earth vanadium oxides under high pressure
by T. Marqueño, D. Errandonea, J. Pellicer-Porres, D. Santamaría-Pérez, P. Rodríguez-Hernández, and A. Muñoz
Author(s): T. Marqueño, D. Errandonea, J. Pellicer-Porres, D. Santamaría-Pérez, P. Rodríguez-Hernández, and A. Muñoz

Zircon-type ${R\mathrm{VO}}_{4}$ compounds (where R = rare-earth atom) constitute a family of ternary oxides which are abundant in both nature and the industrial field. Their structural systematics upon compression has been widely studied. According to the observed systematics, the high-pressure cry…

[Phys. Rev. Materials 6, L060601] Published Wed Jun 01, 2022
1 Jun 2022 at 12:00pm
Tetragonal polymorph of ${\mathrm{BaFe}}_{2}{\mathrm{S}}_{2}\mathrm{O}$ as an antiferromagnetic Mott insulator
by Shi-Jie Song, Yi-Qiang Lin, Bai-Zhuo Li, Si-Qi Wu, Qin-Qing Zhu, Zhi Ren, and Guang-Han Cao
Author(s): Shi-Jie Song, Yi-Qiang Lin, Bai-Zhuo Li, Si-Qi Wu, Qin-Qing Zhu, Zhi Ren, and Guang-Han Cao

We report a tetragonal polymorph of ${\mathrm{BaFe}}_{2}{\mathrm{S}}_{2}\mathrm{O}$ synthesized under high pressures. This $β\text{−}{\mathrm{BaFe}}_{2}{\mathrm{S}}_{2}\mathrm{O}$ phase is structurally characterized by two-dimensional ${\mathrm{Fe}}_{2}\mathrm{O}$ square nets that are sandwiched by …

[Phys. Rev. Materials 6, 055002] Published Fri May 13, 2022
13 May 2022 at 12:00pm
Persistence of correlation-driven surface states in ${\mathrm{SmB}}_{6}$ under pressure
by Soonbeom Seo, Yongkang Luo, S. M. Thomas, Z. Fisk, O. Erten, P. S. Riseborough, F. Ronning, J. D. Thompson, and P. F. S. Rosa
Author(s): Soonbeom Seo, Yongkang Luo, S. M. Thomas, Z. Fisk, O. Erten, P. S. Riseborough, F. Ronning, J. D. Thompson, and P. F. S. Rosa

The proposed topological Kondo insulator ${\mathrm{SmB}}_{6}$ hosts a bulk Kondo hybridization gap that stems from strong electronic correlations and a metallic surface state whose effective mass remains disputed. Thermopower and scanning tunneling spectroscopy measurements argue for heavy surface s…

[Phys. Rev. B 105, 245150] Published Wed Jun 29, 2022
29 Jun 2022 at 12:00pm
Electromotive power generated by pressure gradient in metals with the band Jahn-Teller effect
by Mitsuo Kataoka
Author(s): Mitsuo Kataoka

In band Jahn-Teller (BJT) metals, some lattice distortions with their symmetries different from that of the bulk structure can linearly couple to the BJT electrons, so pressures to produce or enhance such distortions can affect the BJT electrons near the Fermi level. This pressure-electric effect in…

[Phys. Rev. B 105, 214112] Published Mon Jun 27, 2022
27 Jun 2022 at 12:00pm
Structural and vibrational behavior of $2H\text{−}{\mathrm{NbSe}}_{2}$ at high pressures
by Grace P. Chen, Elena Bykova, Maxim Bykov, Eric Edmund, Zi-Yu Cao, Xiao-Jia Chen, Jesse S. Smith, Stella Chariton, Vitali B. Prakapenka, and Alexander F. Goncharov
Author(s): Grace P. Chen, Elena Bykova, Maxim Bykov, Eric Edmund, Zi-Yu Cao, Xiao-Jia Chen, Jesse S. Smith, Stella Chariton, Vitali B. Prakapenka, and Alexander F. Goncharov

The high-pressure structural and vibrational properties of a layered transition metal dichalcogenide $2H\text{−}{\mathrm{NbSe}}_{2}$ were investigated using single-crystal x-ray diffraction and Raman spectroscopy, demonstrating its structural stability up to 35 GPa. The lattice compressibility chang…

[Phys. Rev. B 105, 224114] Published Mon Jun 27, 2022
27 Jun 2022 at 12:00pm
Van Hove singularity induced phonon-mediated superconductivity above 77 K in hole-doped ${\mathrm{SrB}}_{3}{\mathrm{C}}_{3}$
by Ting-Ting Gai, Peng-Jie Guo, Huan-Cheng Yang, Yan Gao, Miao Gao, and Zhong-Yi Lu
Author(s): Ting-Ting Gai, Peng-Jie Guo, Huan-Cheng Yang, Yan Gao, Miao Gao, and Zhong-Yi Lu

To design a phonon-mediated superconductor with transition temperature above the liquid-nitrogen temperature under ambient pressure, we align the Fermi level of compound ${\mathrm{SrB}}_{3}{\mathrm{C}}_{3}$ to a Van Hove singularity by introducing 0.4 hole/f.u., namely \${\mathrm{Rb}}_{0.4}{\mathrm{S…

[Phys. Rev. B 105, 224514] Published Mon Jun 27, 2022
27 Jun 2022 at 12:00pm
High pressure effect in the near-infrared emission of Nd3+-doped alkali silicate glasses
by Israel Montoya Matos
Volume 42, Issue 1, March 2022, Page 1-13
.

16 Dec 2021 at 1:56pm
Exploration of the best reference material on anelastic measurement by cyclic loading under high pressure
by Chao Liu
Volume 42, Issue 1, March 2022, Page 14-28
.

13 Dec 2021 at 9:33am
Three-wall piston-cylinder type pressure cell for muon-spin rotation/relaxation experiments
by Rustem Khasanov
Volume 42, Issue 1, March 2022, Page 29-46
.

16 Dec 2021 at 1:59pm
High pressure structural phase transitions in Dysprosium to 202 GPa
by Kevin M. Hope
Volume 42, Issue 1, March 2022, Page 47-56
.

17 Jan 2022 at 10:21am
High pressure photoluminescence of bismuth-doped yttria-alumina-silica glass
by Mark A. Hughes
Volume 42, Issue 1, March 2022, Page 94-104
.

28 Feb 2022 at 5:33am
Effect of high hydrostatic pressure treatment with room-temperature ionic liquid 1-ethyl-3-methylimidazolium acetate - dimethyl sulfoxide mixture on lipid extraction from Chlorella vulgaris
by Yuki Kojima
Volume 42, Issue 1, March 2022, Page 105-120
.

11 Mar 2022 at 3:08am
Improvement of nano-polycrystalline diamond anvil cells with Zr-based bulk metallic glass cylinder for higher pressures: application to Laue-TOF diffractometer
by Keishiro Yamashita
Volume 42, Issue 1, March 2022, Page 121-135
.

11 Mar 2022 at 3:08am
Review: inactivation of very heat-resistant spores of Bacilus sporothermodurans by high pressure treatment combined with others treatments