The existing and future accelerator facilities at GSI and FAIR (an international Facility for Antiproton and Ion Research) provide unique opportunities for research with ion beams in many different disciplines . The presentation gives a glimpse on the broad activities in the field of materials science and ion-track technology using swift heavy ions of GeV energy and above. The interest in such beams is based on the large energy deposition along the trajectory of each individual ion creating long nanoscopic trails of severe damage. In nanoscience, the small track size in combination with the large ion range (up to 100 µm and more) allows us to overcome limits of planar structuring techniques Several examples will be presented illustrating how to synthesize e.g. nanochannels and nanowires of tailored diameter, length, or shape with special electrical, optical, or thermal properties.
Ion beams at FAIR will permit materials science experiments with unprecedented ranges and intensities. Injecting for instance relativistic ions through a mm-thick diamond anvil of a high-pressure cell into a target under pressure, drives the local atomic structure far from equilibrium. Under such conditions, stabilization of new materials was evidenced via pathways in the phase diagram which are otherwise not accessible but of importance to simulate conditions existing in the Earth mantle. Testing materials behavior in extreme radiation, pressure, and temperature environments will also have a direct application to the understanding of structural materials degradation in next generation accelerator components, fusion and fission reactors, and shielding of equipment in deep space missions.
1. T. Stöhlker et al., Nucl. Instr. Meth. 365, 680 (2015)
Many practical applications of materials are based on the use of the properties caused by point defects, in particular those induced by radiation. Theoretical modeling of defective solids allows one not only explain existing experimental data but also predict the properties of new materials. For low defect concentration it becomes appropriate to model a single point defect in an environment of the remaining solid. In such a molecular cluster model the crystal with a single point defect can be seen as a gigantic molecule and the point defect properties are calculated using any of the methods of the molecular quantum chemistry. There are different possibilities to represent the rest of crystal: embedding into the crystalline environment (embedded cluster model), saturation by additional atoms (saturated-cluster model). However, in the case of a solid solution the single-defect model is not appropriate as the stoichiometry change is introduced by regular substitution of the host-crystal atoms by those of other chemical species. In this case the point-defect models with periodic boundary conditions (cyclic cluster and supercell) are more appropriate. These models allow one to use the computer codes and computational methods applied for both the perfect and defective crystals.
The symmetry aspects and applications of traditional supercell model of defective crystals are considered in [1,2]. Recently a novel site symmetry approach for defective crystal calculations in the supercell model was suggested . It is based on the group-theoretical analysis of the site symmetry of the split Wyckoff positions in the perfect crystal supercell, could be applied to a wide class of defects in crystalline solids and allows one to obtain more realistic values for the corresponding point defect formation energy. The efficiency of site symmetry approach was demonstrated for copper impurity in LiCl crystal , carbon-doped ZnO crystal , oxygen interstitials in corundum , polarons in cerium dioxide .
1. R.A.Evarestov Quantum chemistry of solids. The LCAO first principles treatment of crystals. Springer Series in Solid State Sciences 153, second Edition, Springer, Berlin-Heidelberg (2012)
2. R.A.Evarestov, A.V.Bandura, I.I.Tupitsyn, Theoretical Chemistry Accounts,137,14 (2018)
3. R.A. Evarestov , YE Kitaev , VVPorsev , J Appl Crystallogr, 50,89 (2017)
4. R.A.Evarestov ,S. Piskunov,YF Zhukovskii , Chem. Phys Lett. 682,91 (2017)
5. R.A.Evarestov, A. Platonenko, D. Gryaznov, YF Zhukovskii,; E.A.Kotomin,; Phys. Chem. Chem. Phys. 19, 25245 (2017)
6.R.A.Evarestov, D.Gryaznov, M.Arrigoni, E.A.Kotomin, A.Chesnokov, J. Maier, Phys. Chem. Chem. Phys. 19,8340 (2017)
Large scale research facilities, synchrotron radiation centres, have played a crucial role in fundamental discoveries and in the development of novel functional materials. This is thanks to advancing experimental methods based on superior radiation properties of storage ring based light sources. Namely, high brilliance of the radiation, specific time structure in ns-time domain and wide energy range from IR to hard X-rays are available for various experiments. In my talk, I will focus on the materials research carried out using time-resolved luminescence spectroscopy under VUV-XUV excitation at various research centres like DESY (Hamburg, Germany)  and MAX-IV Lab (Lund, Sweden) .
Synchrotron radiation has been an indispensable tool in the investigation of such short-wavelength emissions as cross-luminescence (CL) with ns decay and 5d-4f emission of rare earth ions . Recent advances in band structure calculations, high demand on ultrafast scintillators for various applications and advancements of photodetectors (e.g., SiPM-s) with sensitivity shifted towards UV have renewed interest to such ultrafast emitters. Multication fluorides with complex band structure, e.g., K2SiF6, exhibit CL in UV-VUV and even visible regions as shown by us using pulsed cathodoluminescence. The studies at storage rings can provide a deep insight into the relevant processes challenging for ultrafast scintillation applications. A particular topic of the synchrotron studies of wide band gap nanomaterials is aimed at understanding the influence of nano-particle size and morphology on the fundamental electronic properties in comparison with bulk materials (see  for Al2O3). The peculiarities revealed via the excitation spectra of various intrinsic and extrinsic emissions in nano-alumina will be discussed. Finally, research challenges and experimental potential for luminescence spectroscopy at the FinEstBeAMS of the MAX IV Lab will be reviewed.
1. G. Zimmerer. Rad. Measurements 42, 859 (2007)
2. T. Balasubramanian, B.N. Jensen, S. Urpelainen, et al., AIP Conf. Proc. 1234, 661 (2010)
3. V.N. Makhov, Phys. Scripta 89, 044010 (2014)
4. M. Oja, E. Tõldsepp, E. Feldbach, et al., Radiat. Meas. 90, 75 (2016)
5. R. Pärna, R. Sankari, E. Kukk, et al., Nucl. Instr. Methd. A 859, 83 (2017)
Tracking the structure of heterogeneous catalysts under operando conditions remains a challenge due to the paucity of experimental techniques that can provide atomic-level information for catalytic metal species. Here we report on the use of X-ray absorption near edge structure (XANES) spectroscopy and artificial neural network for refining the three-dimensional geometry of metal catalysts. Neural network is used to unravel the hidden relationship between the XANES features and catalyst geometry. To train the neural network, we rely on the ab-initio XANES simulations by theoretical spectroscopy codes. Our approach allows one to solve the structure of a metal catalyst from its experimental XANES, as demonstrated here by reconstructing the average size, shape and morphology of well-defined mono- and bimetallic nanoparticles.1 In the case of ultra-small clusters their average size can be estimated. This method is applicable to the determination of the structure of metal catalysts in operando studies and can be generalized to other nanoscale systems. It also allows “on-the-fly” XANES analysis, which is a required step for high-throughput and time-dependent studies, including the “reaction on demand” capabilities.
A.I.F. acknowledges support of this work by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy through Grant DE-FG02- 03ER15476.
1 J. Timoshenko, D. Lu, Y. Lin, A. I. Frenkel, J. Phys. Chem. Lett. 8, 5091-5098 (2017).
Several books have been published recently on various aspects of nanophotonics [1–4], and one of them  is fully devoted to organic nanophotonics. However, as strange as it may seem, molecular aspects of organic nanophotonics are almost not considered in [1–4]. Consequently, such important problems as molecules and molecular complexes, their structure, light absorption and emission, intermolecular charge and energy transfer in disordered organic functional layers, and calculations of the corresponding parameters remained outside the scope of [1–4]. This lecture is specially devoted to theoretical and computational aspects of these problems. Some of them were briefly considered in . However, the main focus in  was on the simulation of nanophotonics structures. On the contrary, this lecture is devoted to modern quantum-chemical methods specially designed recently and currently used in the calculations of parameters required for the best description of excited states in organic molecules and in their intermolecular complexes (exciplexes), which are often characterized by significant intra- and intermolecular charge transfer. The set of these parameters include geometrical (structural) parameters and energy data for ground and excited states, charge and energy transfer parameters, light absorption and emission characteristics, and related properties.
This work was supported by the Russian Science Foundation, (project № 14-43-00052) and by the improving of the competitiveness program of National Research Nuclear University “MEPhI”.
1. Principles of Nanophotonics, M. Ohtsu, K. Kobayashi, T. Kawazoe, T. Yatsui, and M. Naruse, CRS Press, 2008, 231 pp.
2. Amorphous Nanophotonics, Carsten Rockstuhl and Toralf Scharf, Editors, DOI 10.1007/978-3-642-32475-8, Springer: Heidelberg, New York, Dordrecht, and London, 2013, 380 pp.
3. Progress in Nanophotonics, Vol. 3, M. Ohtsu and T. Yatsui, Editors, Springer, 2015, 221 pp.
4. Organic Nanophotonics Fundamentals and Applications, Yong Sheng Zhao, Editor, Springer: Heidelberg, New York, Dordrecht, and London, 2015, 214 pp.
5. Atomistic Multiscale Simulation of Nanostructured Materials for Photonic Applications, A. Bagaturyants and M. Vener, Pan Stanford Publishing, 2017, 274 pp.
The title of my talk is the same as the title of our joint Project with Taiwanese colleagues, supported by the Russian Foundation for Basic Research (RFBR) from the Russian part and by the Ministry of Science and Technology (MOST), Taiwan. Mitch M.-C. Chou is Taiwanese Principal Investigator, he is responsible for the crystal growth and characterization by different X-ray and microscopy methods. I am Russian Principal Investigator and in addition to my group, two groups from Kazan’ are involved into the Project. Gilman Shakurov from Zavoisky Physical-Technical Institute characterizes the crystals by EPR methods but the group of Sergei Moiseev carries out photon-echo experiments and measures coherence times of hyperfine levels selected to build a three-level system for optical quantum memory.
In my talk, I’ll briefly discuss the following points:
- Quantum informatics: quantum bits (qubits), quantum memory, quantum computer;
- Three-level Λ and V systems for optical quantum memory;
- Λ systems based on hyperfine levels of impurity centers in crystals;
- Requirements for crystals for optical quantum memory;
- A list of promising crystals;
- Several examples of our research [1-3].
Support by the Russian Foundation for Basic Research (Grant No 18-52-52001) is acknowledged.
1. M. N. Popova, Materials for optical memory: Resolved hyperfine structure in KY3F10:Ho3+. Optical Materials, 35, 1842 (2013).
2. M.N. Popova, Resolved hyperfine structure in the spectra of crystals for optical quantum memory, European Physical Journal Conferences 103, 01011 (2015).
3. M.N. Popova, K.N. Boldyrev, High-resolution spectra of LiYF4:Ho3+ in a magnetic field, Optical Materials 63, 101 (2017).
Recent studies revealed several new classes of piezoelectrics including 2D materials (graphene)  and biomolecular crystals (self-assembled peptides, amino acids, nucleotides) [2,3,4] Piezoelectricity in these occurs because of symmetry breaking on the surface in the first case and presence of highly anisotropic hydrogen bonds in the second. Graphene in contact with oxides offers extremely high piezoelectric activity due to polarity of C-O bonds, while peptide nanotubes (PNTs) demonstrate excellent electromechanical properties due to self-assembly and intrinsic softness of directed hydrogen bonds. Remarkably stable structure, possibility of functionalization together with biocompatibility and easy synthesis and nanofabrication, make graphene, PNTs and other biomolecular crystals (e.g. amino acid glycine ) attractive alternatives to traditional lead-based piezoelectrics.
In this presentation, the mechanisms of piezoelectric effect in these structures will be delineated and methods for their studies will be introduced. Hybrid Piezoresponse Force Microscopy (Hybrid-PFM) will be presented allowing nanoscale electromechanical measurements during acquisition of force-distance curves . Several demonstrators including piezoelectric membranes based on 2D materials (graphene), cantilevers based on PNTs, and piezoelectric scaffolds for cardiomyocite cells  will be presented. Recent results on piezoelectricity and pyroelectricity in PNTs show that they are very attractive for various piezoelectric applications in biomedicine, because of their intrinsic biocompatibility combined with mesoporous structure and ability to work in contact with living cells and biological liquids. Scaling of piezomaterials down to nanosize is expected to dramatically improve their performance, thus making nanoscale piezoelectrics more sensitive than the traditional ones.
16:40 bus leaving
The intriguing properties of low-dimensional organic conductors distinguish them as interesting candidates for thermoelectric applications. In particular, their anisotropic metallic-like electrical conductivity reaching values of up to 105 S/m at room temperature in combination with a poor thermal transport characteristic for weak van-der-Waals bound crystals favor figures of merit, zT = (σ S2/κ)T, that are of technological relevance. By the correlated electron system and its strong coupling to the surrounding lattice remarkable phenomena emerge, like phonon drag effects or the violation of the Wiedemann-Franz law, which support the implementation of organic conductors in future thermoelectrics even further .
After introductory remarks on low-dimensional organic conductors and their correlated structural and electronic properties, we will demonstrate by means of two representatives of this class, the n-conducting DCNQI2Cu radical ion salt and the one-dimensional p-conductor TTT2I3, the complex thermoelectric behavior as function of temperature (see Fig. 1) . Based on this information and the interdependence of the relevant quantities an all-organic thermoelectric generator comprised of the two organic conductors will be presented as a proof-of-concept and compared in its performance with alternative approaches. Strategies to further improve the thermoelectric performance of these low-dimensional organic conductors and their technological potential will be highlighted.
1. F. Huewe et al., Phys. Rev. B 92, 155107 (2015)
2. F. Huewe, et al., Adv. Mater. 29, 1605682 (2017)
The CO2EXIDE project aims at the development of a combined electrochemical-chemical technology for the simultaneous electrocatalytic conversion of CO2 to ethylene at the cathode, water oxidation to hydrogen peroxide at the anode and a subsequent chemical conversion of both intermediates to ethylene oxide and oligo-/polyethylene glycol in a cascade reaction. Within the project duration, the final CO2EXIDE technology will undergo a thorough material and component R&D programme. A 1kW PEM electrolyser for CO22-reduction and water oxidation in combination with an ethylene enrichment unit and subsequent chemical conversion cascade reactor will be manufactured to produce ethylene oxide as intermediate for oligo-/polyethylene glycol synthesis.
For example, by using template-assisted electrodeposition it is possible to obtain hexagonally arranged nanowire arrays with huge active surface for electrocatalysis. Using e.g. 55 nm pore diameter alumina templates with 1 cm2 geometrical area to obtain 200 nm long nanowires it is possible to get material with estimated 1357 m2 active lateral surface. This can be easily improved by increasing the length of nanowires by introducing different shapes (periodically modulated or Y-branched) or by producing binary nanowires and etched on of components to obtain porous nanostructures. Examples of nanostructures obtained via template-assisted electrodeposition are presented in Figure 1.
Within the presentation, a detailed description of the CO2EXIDE project and the materials development for nanomaterials as well as 3D-electrodes will be presented.
References: Brzózka A., Brudzisz A., Hnida K., Sulka G.D. (2015) Chemical and Structural Modifications of Nanoporous Alumina and Its Optical Properties. In: Losic D., Santos A. (eds) Electrochemically Engineered Nanoporous Materials. Springer Series in Materials Science, vol 220. Springer, Cham.
Acknowledgement: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 768789.