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.

Optimal depth of subvolcanic magma chamber growth controlled by volatiles and crust rheology
by Christian Huber

Nature Geoscience, Published online: 19 August 2019; doi:10.1038/s41561-019-0415-6

Volatile exsolution and crustal viscosity dictate that the optimum pressure for the growth of an eruptible magma reservoir is 2 kbar in all tectonic settings and crustal compositions, according to thermomechanical modelling.
19 Aug 2019 at 12:00am
Active cell migration is critical for steady-state epithelial turnover in the gut
by Krndija, D., El Marjou, F., Guirao, B., Richon, S., Leroy, O., Bellaiche, Y., Hannezo, E., Matic Vignjevic, D.

Steady-state turnover is a hallmark of epithelial tissues throughout adult life. Intestinal epithelial turnover is marked by continuous cell migration, which is assumed to be driven by mitotic pressure from the crypts. However, the balance of forces in renewal remains ill-defined. Combining biophysical modeling and quantitative three-dimensional tissue imaging with genetic and physical manipulations, we revealed the existence of an actin-related protein 2/3 complex–dependent active migratory force, which explains quantitatively the profiles of cell speed, density, and tissue tension along the villi. Cells migrate collectively with minimal rearrangements while displaying dual—apicobasal and front-back—polarity characterized by actin-rich basal protrusions oriented in the direction of migration. We propose that active migration is a critical component of gut epithelial turnover.

15 Aug 2019 at 7:39pm
Water and methane stay together at extreme pressures [Chemistry]
by Christoph G. Salzmann
Large lakes of liquid methane nestle between mountain ranges of solid water ice in the polar regions of Jupiter’s moon Titan (1, 2). This strange world illustrates in a quite dramatic fashion that the isoelectronic CH4 and H2O molecules display profoundly different physical properties including a 182 °C difference in...
13 Aug 2019 at 7:11pm
Pore-pressure diffusion, enhanced by poroelastic stresses, controls induced seismicity in Oklahoma [Earth, Atmospheric, and Planetary Sciences]
by Guang Zhai, Manoochehr Shirzaei, Michael Manga, Xiaowei Chen
Induced seismicity linked to geothermal resource exploitation, hydraulic fracturing, and wastewater disposal is evolving into a global issue because of the increasing energy demand. Moderate to large induced earthquakes, causing widespread hazards, are often related to fluid injection into deep permeable formations that are hydraulically connected to the underlying crystalline...
13 Aug 2019 at 7:11pm
Volumetric and shear processes in crystalline rock approaching faulting [Earth, Atmospheric, and Planetary Sciences]
by Francois Renard, Jessica McBeck, Neelima Kandula, Benoit Cordonnier, Paul Meakin, Yehuda Ben–Zion
Understanding the approach to faulting in continental rocks is critical for identifying processes leading to fracturing in geomaterials and the preparation process of large earthquakes. In situ dynamic X-ray imaging and digital volume correlation analysis of a crystalline rock core, under a constant confining pressure of 25 MPa, are used...
13 Aug 2019 at 7:11pm
The vapor pressure of liquid and solid water phases at conditions relevant to the atmosphere
by Mario Nachbar
The Journal of Chemical Physics, Volume 151, Issue 6, August 2019.
In the atmosphere, water can be present in liquid and solid phases, but the vapor phase is generally predominant. Condensed phases of water occur under a wide range of conditions, ranging from polar mesospheric clouds at the lowest atmospheric temperatures and at low pressure to the much warmer tropospheric clouds. The temperature range at which ice or water clouds are observed spans from T = 100 to 300 K with pressures ranging from about 10−3 mbar to about 1 bar. Over this wide range, water is known to form several condensed phases, which can be separated into crystalline (hexagonal and stacking disordered ice) and noncrystalline phases (liquid and supercooled liquid water, amorphous solid water). We report on the vapor pressure of these water phases with a focus on metastable amorphous solid water and stacking disordered ice in the light of recent experimental findings and discuss possible implications for the atmosphere. We present evidence that supercooled liquid water and low density amorphous solid water do not belong to the same phase and therefore, no continuous vapor pressure curve can be given.
9 Aug 2019 at 4:50am
Glass transition of LiCl aqueous solutions confined in mesoporous silica
by M. Paula Longinotti
The Journal of Chemical Physics, Volume 151, Issue 6, August 2019.
The thermal transitions of confined LiCl aqueous solutions were studied by differential scanning calorimetry for solutions with salt concentrations with eutectic (R = 7) and subeutectic (R > 7) compositions (R = moles of water/moles of LiCl). The confinement media consist of mesoporous silica with pore diameters between 2 nm and 58 nm, with a small negative surface charge density. The vitrification of confined LiCl aqueous solutions was observed in all samples, expanding the vitrification region up to R = 15, and probably beyond for cooling rates of ≈1000 K/min. Ice crystallization was observed in some samples, except for those confined in the narrower pores. The onset and endpoint glass transition temperatures for the confined eutectic samples increase by 2 K and 5 K, respectively, for the smallest pore diameters (2 nm), which is equivalent to the effect of applying a pressure of up to 100 MPa to the bulk sample. This behavior is opposite of that reported for aqueous subeutectic NaCl solutions confined in silica glasses of similar sizes. We speculate that this is due to the fact that the mechanism of double confinement of the NaCl solution, between the pore wall and the precipitated ice, is not operative for LiCl solutions. Instead, the Li+ ions might force the hydration water in to a high-density state.
13 Aug 2019 at 7:38am
Analysis of individual molecular dynamics snapshots simulating wetting of surfaces using spheroidal geometric constructions
by Aleksandr Abramov
The Journal of Chemical Physics, Volume 151, Issue 6, August 2019.
Accurate characterization of wettability of minerals is important for efficient oil recovery and carbon geosequestration. In studies where molecular dynamics simulations are used to compute the contact angle, emphasis is often placed on results or theoretical details of the simulations themselves, overlooking potentially applicable methodologies for determination of the contact angle. In this manuscript, a concept of a method utilizing spheroidal geometric constructions to estimate the contact angle of a water droplet on a silica surface in carbon dioxide atmosphere is outlined and applied to the final snapshots of two molecular dynamics simulation runs. Two carbon dioxide pressures and two wettability modes (hydrophilic and hydrophobic) are examined to assess the method’s performance. The most stable 6-membered ellipselike rings (001) pristine surface of alpha-quartz is reconstructed using molecular dynamics and its wettability is then investigated for the first time. The outcomes of the calculations are compared with results produced with the isodensity chart method, and good agreement with the latter approach is demonstrated. The proposed method can be used as an alternative, or in conjunction with other techniques, to increase the confidence in contact angle estimations via molecular mechanics calculations. Reliable contact angle estimations, on the other hand, can guarantee accurate storage capacity and security of carbon capture and storage projects.
9 Aug 2019 at 4:50am
Hydrogen-Induced High-Temperature Superconductivity in Two-Dimensional Materials: The Example of Hydrogenated Monolayer ${\mathrm{MgB}}_{2}$
by J. Bekaert, M. Petrov, A. Aperis, P. M. Oppeneer, and M. V. Milošević
Author(s): J. Bekaert, M. Petrov, A. Aperis, P. M. Oppeneer, and M. V. Milošević

Hydrogen-based compounds under ultrahigh pressure, such as the polyhydrides ${\mathrm{H}}_{3}\mathrm{S}$ and ${\mathrm{LaH}}_{10}$, superconduct through the conventional electron-phonon coupling mechanism to attain the record critical temperatures known to date. Here we exploit the intrinsic advanta...

[Phys. Rev. Lett. 123, 077001] Published Tue Aug 13, 2019
13 Aug 2019 at 12:00pm
Scaling Laws of an Exploding Liquid Column under an Intense Ultrashort X-Ray Pulse
by Alfonso M. Gañán-Calvo
Author(s): Alfonso M. Gañán-Calvo

A proposed general formulation of the partial destruction of a liquid object in vacuum impacted by an ultrashort x-ray pulse suggests that energy instantaneously raises the pressure of a portion of the liquid to extreme values and causes its explosive expansion into vacuum.

[Phys. Rev. Lett. 123, 064501] Published Wed Aug 07, 2019
7 Aug 2019 at 12:00pm
Pressure-Induced Hydrogen-Hydrogen Interaction in Metallic FeH Revealed by NMR
by Thomas Meier, Florian Trybel, Saiana Khandarkhaeva, Gerd Steinle-Neumann, Stella Chariton, Timofey Fedotenko, Sylvain Petitgirard, Michael Hanfland, Konstantin Glazyrin, Natalia Dubrovinskaia, and Leonid Dubrovinsky
Author(s): Thomas Meier, Florian Trybel, Saiana Khandarkhaeva, Gerd Steinle-Neumann, Stella Chariton, Timofey Fedotenko, Sylvain Petitgirard, Michael Hanfland, Konstantin Glazyrin, Natalia Dubrovinskaia, and Leonid Dubrovinsky

Nuclear magnetic resonance experiments reveal how the electronic properties of hydrogen in iron hydride change under extreme pressure, a step toward understanding the onset of high-temperature superconductivity in metal hydrides.

[Phys. Rev. X 9, 031008] Published Wed Jul 17, 2019
17 Jul 2019 at 12:00pm
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
Formation of graphene atop a Si adlayer on the C-face of SiC
by Jun Li, Qingxiao Wang, Guowei He, Michael Widom, Lydia Nemec, Volker Blum, Moon Kim, Patrick Rinke, and Randall M. Feenstra
Author(s): Jun Li, Qingxiao Wang, Guowei He, Michael Widom, Lydia Nemec, Volker Blum, Moon Kim, Patrick Rinke, and Randall M. Feenstra

The structure of the SiC($000\overline{1}$) surface, the C-face of the {0001} SiC surfaces, is studied as a function of temperature and of pressure in a gaseous environment of disilane ($\mathrm{S}{\mathrm{i}}_{2}{\mathrm{H}}_{6}$). Various surface reconstructions are observed, both with and without...

[Phys. Rev. Materials 3, 084006] Published Mon Aug 19, 2019
19 Aug 2019 at 12:00pm
Atomic-scale coexistence of short-range magnetic order and superconductivity in ${\mathrm{Fe}}_{1+y}{\mathrm{Se}}_{0.1}{\mathrm{Te}}_{0.9}$
by Ramakrishna Aluru, Haibiao Zhou, Antoine Essig, J.-Ph. Reid, Vladimir Tsurkan, Alois Loidl, Joachim Deisenhofer, and Peter Wahl
Author(s): Ramakrishna Aluru, Haibiao Zhou, Antoine Essig, J.-Ph. Reid, Vladimir Tsurkan, Alois Loidl, Joachim Deisenhofer, and Peter Wahl

The ground state of the parent compounds of many high-temperature superconductors is an antiferromagnetically ordered phase, where superconductivity emerges when the antiferromagnetic phase transition is suppressed by doping or application of pressure. This behavior implies a close relation between ...

[Phys. Rev. Materials 3, 084805] Published Mon Aug 19, 2019
19 Aug 2019 at 12:00pm
In situ observation of material flow in composite media under shock compression
by David B. Bober, Jonathan Lind, and Mukul Kumar
Author(s): David B. Bober, Jonathan Lind, and Mukul Kumar

When a shock wave enters a heterogeneous material, local differences in density and compressibility drive pressure and velocity gradients which can be nearly as sharp as the incident shock. Subsequent momentum equilibration is comparatively slow, relying on shock reverberation, particle collisions, ...

[Phys. Rev. Materials 3, 073603] Published Mon Jul 22, 2019
22 Jul 2019 at 12:00pm
Time-reversal symmetry breaking in topological superconductor ${\mathrm{Sr}}_{0.1}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$
by P. Neha, P. K. Biswas, Tanmoy Das, and S. Patnaik
Author(s): P. Neha, P. K. Biswas, Tanmoy Das, and S. Patnaik

The single helical Fermi surface on the surface state of three-dimensional topological insulator ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ is constrained by the time-reversal invariant bulk topology to possess a spin-singlet superconducting pairing symmetry. In fact, the Cu-doped and pressure-tuned super...

[Phys. Rev. Materials 3, 074201] Published Tue Jul 16, 2019
16 Jul 2019 at 12:00pm
High-pressure phase of $\mathrm{CrS}{\mathrm{b}}_{2}$: A new quasi-one-dimensional itinerant magnet with competing interactions
by Y. Y. Jiao, Z. Y. Liu, M. A. McGuire, S. Calder, J.-Q. Yan, B. C. Sales, J. P. Sun, Q. Cui, N. N. Wang, Y. Sui, Y. Uwatoko, B. S. Wang, X. L. Dong, and J.-G. Cheng
Author(s): Y. Y. Jiao, Z. Y. Liu, M. A. McGuire, S. Calder, J.-Q. Yan, B. C. Sales, J. P. Sun, Q. Cui, N. N. Wang, Y. Sui, Y. Uwatoko, B. S. Wang, X. L. Dong, and J.-G. Cheng

We have synthesized the high-pressure form of $\mathrm{CrS}{\mathrm{b}}_{2}$ with $\mathrm{CuA}{\mathrm{l}}_{2}$-type structure under 7 GPa and 700 °C, and characterized its structural, transport, and magnetic properties by a suite of measurement techniques over a broad range of temperature, magneti...

[Phys. Rev. Materials 3, 074404] Published Thu Jul 11, 2019
11 Jul 2019 at 12:00pm
High-pressure melting curve of sulfur up to 65 GPa
by Sarah M. Arveson, Yue Meng, June Lee, and Kanani K. M. Lee
Author(s): Sarah M. Arveson, Yue Meng, June Lee, and Kanani K. M. Lee

The melting curve of elemental sulfur was measured to pressures of 65 GPa in a laser-heated diamond-anvil cell using ex situ textural analyses combined with spectroradiometry and benchmarked with laser-power-temperature functions. The melting curve reaches temperatures of $∼1800\phantom{\rule{0.28em... [Phys. Rev. B 100, 054106] Published Thu Aug 15, 2019 15 Aug 2019 at 12:00pm Role of the Fermi surface for the pressure-tuned nematic transition in the${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$family by Elena Gati, Li Xiang, Sergey L. Bud'ko, and Paul C. Canfield Author(s): Elena Gati, Li Xiang, Sergey L. Bud'ko, and Paul C. Canfield The tetragonal-to-orthorhombic phase transition at${T}_{s}$, which precedes the antiferromagnetic phase transition at${T}_{N}$in many iron-based superconductors, is considered one of the manifestations of electronic nematic order. By constructing temperature-pressure phase diagrams of pure and Co... [Phys. Rev. B 100, 064512] Published Thu Aug 15, 2019 15 Aug 2019 at 12:00pm Ground states of$\mathrm{A}{\mathrm{u}}_{2}\mathrm{Pb}$and pressure-enhanced superconductivity by Juefei Wu, Zili Feng, Jinghui Wang, Qun Chen, Chi Ding, Tong Chen, Zhaopeng Guo, Jinsheng Wen, Youguo Shi, Dingyu Xing, and Jian Sun Author(s): Juefei Wu, Zili Feng, Jinghui Wang, Qun Chen, Chi Ding, Tong Chen, Zhaopeng Guo, Jinsheng Wen, Youguo Shi, Dingyu Xing, and Jian Sun$\mathrm{A}{\mathrm{u}}_{2}\mathrm{Pb}$is a candidate of natural topological superconductors that has attracted much attention in the last few years. Combining ab initio calculations with machine-learning accelerated crystal structure searches, we have found two ground states of$\mathrm{A}{\mathrm...

[Phys. Rev. B 100, 060103(R)] Published Mon Aug 12, 2019
12 Aug 2019 at 12:00pm
Universal relationship between low-energy antiferromagnetic fluctuations and superconductivity in ${\mathrm{BaFe}}_{2}{({\mathrm{As}}_{1−x}{\mathrm{P}}_{x})}_{2}$
by Shunsaku Kitagawa, Takeshi Kawamura, Kenji Ishida, Yuta Mizukami, Shigeru Kasahara, Takasada Shibauchi, Takahito Terashima, and Yuji Matsuda
Author(s): Shunsaku Kitagawa, Takeshi Kawamura, Kenji Ishida, Yuta Mizukami, Shigeru Kasahara, Takasada Shibauchi, Takahito Terashima, and Yuji Matsuda

To identify the key parameter for optimal superconductivity in iron pnictides, we measured the $^{31}\mathrm{P}$-NMR relaxation rate on ${\mathrm{BaFe}}_{2}{({\mathrm{As}}_{1−x}{\mathrm{P}}_{x})}_{2}\phantom{\rule{4pt}{0ex}}(x=0.22$ and 0.28) under pressure and compared the effects of chemical subst...

[Phys. Rev. B 100, 060503(R)] Published Mon Aug 12, 2019
12 Aug 2019 at 12:00pm
Development of a technique for high pressure neutron diffraction at 40 GPa with a Paris-Edinburgh press
by T. Hattori
Volume 39, Issue 3, September 2019, Page 417-425
.

4 Jun 2019 at 6:21am
Modified Bridgman anvils for high pressure synthesis and neutron scattering
by Bianca Haberl
Volume 39, Issue 3, September 2019, Page 426-437
.

17 Jun 2019 at 8:18am
Ultrahigh pressure equation of state of tantalum to 310 GPa
by Kaleb C. Burrage
Volume 39, Issue 3, September 2019, Page 489-498
.

11 Jul 2019 at 8:28am
In-situ X-ray diffraction study on β-CrOOH at high pressure and high-temperature
by Chikara Shito
Volume 39, Issue 3, September 2019, Page 499-508
.

17 Jul 2019 at 2:46pm
Effects of high hydrostatic pressure on β-glucan content, swelling power, starch damage, and pasting properties of high-β-glucan barley flour
by Shigeaki Ueno
Volume 39, Issue 3, September 2019, Page 509-524
.

29 Mar 2019 at 1:58pm
The usage of high hydrostatic pressure (HHP) to control food-borne pathogens in hummus
by Barbara Sokołowska
Volume 39, Issue 3, September 2019, Page 525-532
.

24 Jun 2019 at 12:09pm
Lattice distortion-induced sluggish phase transition in CoCrFeNixAl1-x (x = 0.5, 0.75) high-entropy alloys at high pressures
by Lei Liu
.

16 Aug 2019 at 12:07pm