Institute of High Pressure Physics

Two researchers from the Institute of High Pressure Physics of the Polish Academy of Sciences (IHPP PAS, Unipress) will deliver presentations at an international online seminar organized by the International Solvothermal and Hydrothermal Association (ISHA) within the ISHA Seminar 2026 Series.

The seminar will take place on January 26, 2026, from 12:00 to 14:00 (CET) and will focus on advanced topics related to the ammonothermal growth of gallium nitride (GaN) crystals, covering fundamental aspects of the process as well as the current state of the art and future development perspectives. During the seminar:

• Dr. Tomasz Sochacki - “Ammonothermal Growth of GaN Crystals: From Fundamentals to the State of the Art”,
• MSc. Marek Zak - “Insights into Ammonothermal GaN Crystallization: Computational Modeling, Process Optimization, and Future Technology Scaling”.

The session Chairperson will be Dr. Saskia Schimmel from Friedrich-Alexander-Universität Erlangen–Nürnberg (FAU), Germany.

The seminar will be held online via Zoom platform. Participation is free of charge upon prior registration.

Link to registration

Ammonothermal GaN crystals and substrates. Fot. T. Sochacki IHPP PAS.

We are pleased to share that the article “Spontaneous and Piezo Polarization Versus Polar Surfaces: Fundamentals and Ab Initio Calculations” by P. Strak, P. Kempisty, K. Sakowski, J. Piechota, I. Grzegory, E. Monroy, A. Kaminska, and S. Krukowski, has been selected as an Editor’s Choice Article in the Materials journal by MDPI. The selection was made after a thorough evaluation by the journal’s Academic Editors, recognizing the paper for its academic originality, relevance to cutting-edge topics, rigorous argumentation, and clarity of structure, and the expectation that it will attract broad interest and academic attention.

This paper presents fundamental insights into the interplay between spontaneous and piezoelectric polarization at polar surfaces, supported by ab initio (first-principles) computational analysis. The study advances understanding of how electric polarization phenomena influence the properties and stability of polar materials – a topic of high relevance for electronic, optoelectronic, and energy materials research. We congratulate the authors on this achievement and encourage to learn more about this work.

CaKFe₄As₄ is already superconducting without chemical doping, unlike most iron-based superconductors. This unique characteristic makes it an ideal platform for investigating the effects of selective elemental substitution within the superconducting FeAs layers.

In this context, Prof. Shiv J. Singh’s research team (from NL-6 Laboratory of Superconductors and Hydrogen Technologies) systematically investigated the influence of Mn substitution combined with high-pressure synthesis on the superconducting properties of CaKFe₄As₄. Mn-doped CaK(Fe_1-xMn_x)₄As₄ bulk samples were successfully synthesized using both conventional solid-state processing and high-pressure synthesis techniques.

Although Mn doping is generally known to suppress superconductivity in iron-based systems, the application of high-pressure synthesis was found to partially counteract this detrimental effect. As a result, a significant enhancement of the superconducting transition temperature (T_c) by approximately 3–7 K was observed for samples with 2–3% Mn substitution. Moreover, the study reveals unique behaviour in Mn-doped CaKFe₄As₄, where an increase in T_c can be achieved through the combined effects of controlled doping and high-pressure processing.

For more details, please refer to the publication: Manasa Manasa, Mohammad Azam, Tatiana Zajarniuk, Svitlana Stelmakh, Tomasz Cetner, Andrzej Morawski & Shiv J. Singh entitled “Enhancement of the Superconducting Transition Temperature in Mn-doped CaKFe₄As₄ Processed by the High gas-pressure and High-temperature Synthesis Method” Journal of Superconductivity and Novel Magnetism 39, 10 (2026). https://doi.org/10.1007/s10948-025-07115-2

Figure: A comparative summary of the superconducting transition temperatures (T_c) of CaK(Fe_1-xMn_x)₄As₄ bulks prepared by CSP at ambient pressure, and High gas pressure and high temperature synthesis (HP-HTS) methods, together with reported Mn-doped CaKFe₄As₄ single-crystals grown by the conventional method at ambient pressure [22], is shown with Mn concentration (x). The transition temperature values are determined from both the resistivity (R(T)) and magnetic (M(T)) measurements.

We are pleased to announce an invited talk by Dr. Marta Sawicka from the MBE Epitaxy laboratory of our Institute.

Title: Exploring electrochemical etching as a tool for cladding engineering in III-nitride laser diodes.

Dr. Sawicka will present at the UK Nitrides Consortium (UKNC) Winter Meeting on January 7-8, 2026, hosted by Swansea University (United Kingdom). The UKNC provides a vital platform for UK-based industrial and academic researchers to share ideas and advances in nitride semiconductors and related wide bandgap materials.

Detailed program of the conference can be found here.