Preface

• Published in: Physica status solidi. C Vol. 1; no. 11; pp. 2597 - 2598
• Main Authors: Kaplyanskii, Alexander, Akimov, Andrey, Bursian, Viktor
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag 01.11.2004
• ISSN: 1610-1634; 1610-1642
• DOI: 10.1002/pssc.200490024

The conference Phonons 2004 was held 25–30 July 2004 at A. F. Ioffe Physico‐Technical Institute in St Petersburg, Russia. This was the eleventh conference in the triennial series of International Conferences on Phonon Scattering in Condensed Matter, which started in 1972 in St Maxime, France. Previous conferences were held in Nottingham (1975), Providence (1979), Stuttgart (1983), Urbana (1986), Heidelberg (1989), Ithaca (1992), Sapporo (1995), Lancaster (1998), and Dartmouth College (2001). The conferences in Heidelberg and Sapporo were organized jointly with the Conferences on Phonon Physics which were started before in Bloomington (1981) and Budapest (1985). Though since the Sapporo meeting the Conferences on Phonon Scattering in Condensed Matter were not formally combined with the Phonon Physics ones, their range of topics became very wide and the existing single Phonon Scattering triennial conference series provides now the major international forum for all experimental and theoretical work on phenomena and problems involving phonons. Ioffe Institute seemed to be a very appropriate location for the present conference as it was the home of Yakov Frenkel and Peter Kapitza who made key contributions to phonon physics in its early days. Another Ioffe Institute member Eugene Gross was the first who, in 1930, observed experimentally the inelastic scattering of light on acoustic waves in solids. The appearance of the well‐known “Ioffe‐Regel” criterion is also due to the studies performed here. Solid state physics, both experimental and applied, remains to be the main field of scientific activity at Ioffe Institute. The conference Phonons 2004 brought together 204 scientists from 33 countries. The participants were geographically distributed as follows: Russia 61, France 26, Japan 22, USA 12, Germany 11, United Kingdom 9, Ukraine 9, Italy 5, Finland 5, Poland 5, The Netherlands 3, Belarus 2, Belgium 2, Canada 2, Czechia 2, Estonia 2, Israel 2, Moldova 2, Serbia & Montenegro 2, South Africa 2, Spain 2, Switzerland 2, Turkey 2, Australia 1, Austria 1, Hungary 1, India 1, Ireland 1, Mexico 1, PR China 1, Portugal 1, Slovakia 1 and Taiwan 1. In the scientific programme the traditional topics of the conference series, e.g. phonons in glasses and disordered materials, phonon transport and imaging, Raman and neutron scattering, electron–phonon interaction were all represented as well as were new and developing areas: ultrafast acoustics, phonons in nanostructures and phononic crystals. The sessions of Phonons 2004 were held in a separate building of the Educational Centre of the Ioffe Institute, which is allotted for Institute‐based educational units and various scientific meetings. The programme comprised plenary morning sessions, topical parallel sessions and poster sessions. A special session was organized for the presentation of works sponsored by the International Science and Technology Centre. There were five plenary lectures, four invited talks of general interest, nine topical invited talks, 49 oral and 183 poster presentations. At the opening session sad news were announced about the death of two distinguished members of the international scientific phonon community. After a long illness, Prof. Walter Bron, who had made highly significant contributions to phonon physics, passed away. Walter Bron was the organizer of the first International Conference on Phonon Physics in Bloomington, USA (1981). Professor Ija Ipatova tragically died in a car accident. She was a distinguished theoretician in the field of lattice dynamics and was a member of the International Advisory Committee of Phonons 2004. The first plenary lecture given by H. J. Maris was the on subject of acoustic solitons. It was described how a train of strain solitons in a crystal is created by delivering a hard blow to the lattice with a “fast hammer”. In the experiments reviewed, the “hammer” was an ultrafast laser pulse thermalized in a metal film on the crystal surface. This topic was developed in the invited talk by J. I. Dijkhuis, where the interaction of the solitons with the two level system was studied in ruby crystals. The soliton topic moved to experiments where ultrashort acoustic pulses are generated. About ten talks were devoted to this subject, with the studies carried out in semiconductor nanostructures (B. Perrin), liquid mercury (O. B. Wright) and other objects. Two sessions were on the subject of coherent phonons. The generation of coherent optical 15.3 THz phonons was experimentally demonstrated in silicon (H. Petek). The generation of coherent acoustic phonons was realized in semiconductors and dielectrics using continuous and pulsed lasers (D. Lehman, H. W. de Wijn and others). Phonons in different semiconductor nanostructures were the subject of several invited talks at plenary (A. J. Kent, B. H. Bairamov, V. L. Gurevich) and topical sessions. In his plenary lecture A. N. Cleland talked about the progress towards the quantum limit in the performance of nano‐electromechanical systems. A. A. Balandin discussed the theoretical aspects of acoustic phonon confinement in semiconductor nanostructures and its effect on thermal conductivity and cooling of nanoelectronic devices. N. del Fatti spoke about phonons in noble‐metal nanoparticles and selective excitation of their radial mode. E. A. Zibik presented a recent contribution showing the role of polaron coupling in the processes of exciton relaxation in semiconductor quantum dots. The invited talks at plenary sessions were devoted also to THz excitations in glasses (R. Vacher) and to localized vibrational modes in amorphous silicon (J. P. Wells). In the plenary talk given by J. H. Page at the final plenary session, the acoustic propagation in two‐ and three‐dimensional periodic composite materials with lattice spacing comparable to acoustic wavelengths (“phononic crystals”) was described. Phenomena such as resonant tunnelling, focusing of ultrasound and negative refraction were demonstrated. In total the experimental and theoretical studies presented at Phonons 2004 show that phonon physics is still a vibrant and continually evolving area of scientific research. Following the traditions of Phonon Scattering Conferences, in the closing plenary session special tribute was paid to our most active colleagues in phonon studies over many years: Harold de Wijn was presented with the small globe, made from coloured minerals together with the citation “For outstanding contribution to phonons physics – Phonons 2004”. The physica status solidi Young Researcher Award, the Wiley‐VCH prize for the best presentation at the conference by a young scientist, was awarded for the first time to Andrey Naumov (Institute of Spectroscopy, Russia) for his oral talk on studies of low‐temperature dynamics of disordered solids. At the very end the chorus of Ioffe Institute gave a short concert for conference participants. Finally it was announced that the next, 12th Conference on Phonon Scattering in Condensed Matter will be held in Paris in 2007, chaired by Prof. B. Perrin. We would like to express our sincere thanks to all who helped to organize Phonons 2004, especially to the members of the Advisory and Programme Committees. The Organizing Committee acknowledges the financial support from all sponsors. We also hope that the scientific schedule of Phonons 2004 gave a possibility for the conference participants and accompanying persons to visit an interesting cultural program in St Petersburg, known as the cultural capital of Russia. IUPAP Policy on the Free Circulation of Scientists To secure IUPAP sponsorship, the organizers have provided assurance that Phonons 2004 was conducted in accordance with IUPAP principles as stated in the ICSU‐Document “Universality of Science” (sixth edition, 1989) regarding the free circulation of scientists for international purposes. In particular, no bona fide scientist was excluded from participation on the grounds of national origin, nationality, or political considerations unrelated to science.