News
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Older news
 | Congratulation to Ron Cohn Wagner for completing the master program in physics. The concluding master project on the pseudogap phenomenon and its interaction with superconductivity just appeared on the arXiv. This long-standing scientific problem remains unsolved. Yet, the work by Ron and Julia suggests that future technical progress synchrotron photoelectron spectroscopy may help to crack the conundrum.  | |
 | Under the supervision of Qisi Wang, Roger Brunner was one of the three students winning the best experimental proseminar award. Roger spoke about the 2003 Nobel prize going to Abrikosov, Ginzburg and Leggett for the contributions to superconductivity and superfluids. This topic is extremely challenging as it spans from quantum mechanics to medical scanning devices. Congratulations, Roger, with this fine result! | |
 | In the last year, Jaewon has published two papers in Physical Review Letters. The first, featured in Physics, reveals a spatially modulated superfluid state in confined He-4 films. His next paper is about charge stripe order detwinning by uniaxial pressure application to a high temperature superconducting compound. Both topics are long standing fields in condensed matter physics where many expectations are already deeply routed. Yet a prime scientific tenet is that progress cannot be driven by expectations alone. Progress is made on the basis of experimental evidence!  | |
 | Congrats to our new postdoc – Izabela Biało for landing one of the Swiss Government Excellence Scholarships for Foreign Scholars and Artists for the 2022-2023 Academic Year. Izabela will explore quantum matters displaying unconventional superconductivity, in particular, focusing on spin or charge excitations. This project includes the use of state-of-the-art resonant inelastic x-ray scattering instrumentation combined with uniaxial pressure. | |
 | Senior scientist Qisi Wang, and the rest of the team make another step forward in understanding the charge stripes in cuprate high temperature superconductors! By combining RIXS measurements at Paul Scherrer Institut (PSI) with uniaxial pressure application, our team proved that mild uniaxial pressures reorder the charge stripes pattern and pins it to the crystal axis. The fact that the external strain is able to stabilize the stripe phase suggests that the material is in the vicinity of a quantum melting point. The results were published in Nature Communications.  | |
 | Technically, Nehir already left us in October, but she has continued to work on the pulsed field project together with Simon Gerber and Marc Janoschek. This weekend 50 Tesla pulses were achieved for the first time. Over the past 18 months, Nehir has through tenacious effort kept improving the coil winding process. In combination with a new capacitor bank designed build by David Wolf from the electronics workshop, magnetic fields hundred thousand times that of the earth was produced. Thanks Nehir for your great work – we wish you good luck with your next job.  | |
 | Fund raising is an essential part for all startup initiatives. Denys and Dominik have been very successful with condenZero. Recently, condenZero was accepted for the prestigious CERN-BIC program, hosted by the new Park Innovaare at the Paul Scherrer Institute (Switzerland Innovation Park Innovaare ). This excellent news came together with an InnoBooster grant from the Gebert Rüf Stiftung (Foundation). Adding to these achievements, condenZero also won the 2021 edition of the Swiss Innovation Challenge (Swiss Innovation Challenge ). For more information about the project watch this video about condenZero.  | |
 | Fantastic weather, panoramic scenery and excellent Walliser food were the setting for our group retreat in Zermatt. In addition to presentations on soft skills and scientific topics, we had several team building events such as break-out rooms, via ferrata and cooking challenges. Overall an exciting retreat that stimulated both team work and self reflections. Thanks everybody for their contributions and especially to Karin and Daniel for the organization.  | |
 | Lattice vibrations (phonons) are known mediators of charger order and superconductivity. However, in the cuprates, these two phases are thought to be primarily driven by electronic degrees of freedom. In a recent study of Qisi and Karin - using state-of-the-art resonant inelastic x-ray scattering at the Diamond light source (see picture) - they demonstrated how electron-phonon coupling contributes to the formation of long range charge stripe ordering in high temperature cuprate superconductors.  | |
 | Over some time, Damian has designed and produced three different types of uniaxial pressure cells for scattering experiments. Common to these holders is that they are operated by a simple screw mechanism. The first cell was designed with pressure application perpendicular to the horizontal scattering plane (see arXiv). This holder was then adapted for in-scattering-plane pressure application and used for both neutron and x-ray scattering. Most recently, Damian re-purposed and improved an in-situ cleaving device for RIXS experiments. All the mentioned pressure devices have generated successful experiments!  | |
 | Just before Christmas last year, Julia went alone (as a first year PhD student) to a ten day long synchrotron experiment. With a bit of help from the local instrument responsible and some remote advises, Julia succeeded a technically challenging project. A previous news feed already high-lighted Julia’s sample preparation skills. These skill sets and achievements are now rewarded with a two year grant from the German 'Studienstiftung des deutschen Volkes'. | |
 | About two years ago, Sara Mustafi joined the UZH condensed matter master program in physics. Through discipline and hard work, Sara did tremendous progress in her studies and finished this summer exactly within the nominated time. Her master thesis project dealt with magnon-magnon interaction in cuprates with large ring exchange interaction. Even Sara has been recruited for a PhD project at the PSI laboratory for nano-scale biology, we hope to accomplish a manuscript reporting on this study. Sara, congrats and good luck with the new job. | |
 | Team work can enable achievements that are out-of-reach for a single person. The last months have provided us with a perfect example of this. In this fashion Gediminas, Niels and Daniel succeed an amazing neutron scattering experiment. Uniaxial pressure cells were designed by Damian at UZH and manufactured at DTU-Copenhagen and PSI-Switzerland. Single crystals were grown in record time in Sapporo – Japan by Tohru Kurosawa and his colleagues. With dedicated effort, Julia with assistance from Gediminas and Daniel managed to prepare the crystals less than 24 hours before the experiment. Finally, the success of the experiment relied on many years of instrumental development at Institut Laue-Langevin (ILL). In the picture, Daniel (left) and Niels (right) discuss instrumental configurations.  | |
 | Having worked on 3D metal printed structures together with Alexander and Denys, Annabella defended her bachelor thesis this week. The objective was to understand Helium leak properties of metal printed structures. Annabella and Alexander constructed a setup for leak testing while the temperature of the printed structure is varied. The photo shows a polished surface seen from an optical microscopic. | |
 | Having established a cotutelle agreement between UZH and Chalmers University of Technology in Gothenburg (already an achievement), Karin has started a fund raising campaign. As a first result, Karin was awarded the prestigious FAN grant that covers 1/3 of her stay at Chalmers. Now it is all about converting the scientific proposals to study cuprates and heavy Fermions using ARPES and RIXS techniques. | |
| | In this video, Denys and Dominik speak about their vision for cryo-TEM and their entrepreneurial ambitions. Thanks to ventureKick for producing this video and for enrolling condenZero into their entrepreneurial program! | |
 | Are metallic additively manufactured parts leak-tight? A common perception is that perfect leak tightness is not easily achieved. While building condenZero, Denys and Dominik have found a process to reach such leak tightness. To explore potential market opportunities and related space applications, condenZero has obtained funding from the ESA BIC Switzerland program. | |
 | We have previously reported about the condenZero project (initiated by Denys and Dominik) being in the Venture-Kick semi-final. Just as the development of the cryo-TEM holder is progressing, the project has advanced to the Venture-Kick final that will take place in Spring 2021. Image is a high voltage electron bombardment arrangement used in the manufacturing. | |
 | Karin’s master thesis work on Ca3Ru2O7 studied by high resolution RIXS has been awarded a UZH semester prize. At the same time, the work is accepted for publication in Physical Review B. Due to the pandemic the celebration ceremony was cancelled and hence we cannont provide a picture of Karin getting the award. Instead the front-cover of last years institute annual report is featured here. | |
 | Eccellenza is the largest and most prestigious young scientist grant in Switzerland. This month, it was announced that Fabian von Rohr is one of the young talents selected in the 2020 round. Starting in February 2021, Fabian will enter as a faculty member. This grant will also strengthen materials discovery – a field living on the boarders between the classical disciplines of physics and chemistry. | |
| | We are always happy to receive requests for bachelor and master project opportunities. In this video clip, we feature our synchrotron research activities. For an impression of our physics department watch this video. | |
 | After working with us for a bit more than three years, Masafumi continues his career as an assistant professor at the University of Tokyo. In his new job, Masafumi will be based at the Spring8 synchrotron. During his time in Zurich, Masafumi was very productive and at the same time very supportive with younger colleagues. We will miss Masafumi and his helpful spirit, friendly character and Ferrari beam-time motor. Hopefully, we can keep collaborating and have scientific exchanges with you. Good luck Masafumi! | |
 | Together with Dominik, Denys is building a new prototype cryo-TEM holder and this is laying the foundation for the spin-off company condenZero. In this context, Denys has won an Innosuisse startup Coaching voucher. Denys says: “The coaching will help us to further develop our business with regard to strategy, market viability and legal guidance.” | |
| | The experimental proseminar gives bachelor students the opportunity to give their first scientific presentation. This spring semester has been operated in a digital mode and hence students recorded their presentation before uploading on YouTube. Despite this new format, our students adapted very well and delivered interesting talks. An example is Christopher Binz’s talk about Louis Néel’s Nobel-prize work on antiferromagnetism. On this tour, Christopher demonstrates the power of neutron scattering by covering also the work of Nobel laureate Clifford Shull. Another example is Stefanie Jucker’s talk about fullerenes. | |
 | Charge stripe order has long been known to co-exist with high-temperature superconductivity in copper-oxide materials. A common perception is that this stripe order is a consequence of a peculiar low-temperature tetragonal lattice (LTT) structure. In a recent paper accepted in Physical Review Letters, Qisi reports how stripe order persists far above the LTT structure transition. Stripe order is therefore a primary rather than secondary effect. | |
 | While working on a pulsed-magnetic-field setup for diffraction experiments, Dominik Biscette invented a new type of cryostat. A patent application was handed-in early 2019 and recently a revised version submitted for a second-round review. Details about Dominik’s invention will follow once the patent review is concluded. | |
 | Recently, Venture Kick decided to support four new high-potential start-up companies. The condenZero project is one of the startups selected for a “kick”. Congratulations to Denys. This is certainly going to accelerate the prototyping of a new cryo-holder for transmission electron microscopes. | |
 | In a recently published x-ray diffraction study, with Jaewon as the leading author, we show how ferro- and antiferro-coupled charge-density-wave orders interact differently with superconductivity in YBa2Cu3O7-x. It is demonstrated how the magnetic-field induced ferro-coupled charge density wave competes much stronger with superconductivity than the antiferro component does. These different competing interactions generate an inhomogenous superconducting state. This work is published in Nature Communications. | |
 | Recently, 11 young researchers were awarded the Proof of Concept grant from the Swiss National Science Foundation (SNSF) & Innosuisse (Link). With his project to make a new cryogenics tool for transmission electron microscopy (TEM) (Link), Denys Sutter is one of the awardees. As TEM is applied widely from medicine & biology to physics and semiconductor industries, the project holds great potential and we wish Denys good luck. | |
 | Congratulations to Karin von Arx, the winner of the DECTRIS Experimental Physics Prize! The Prize is given to an excellent Master's thesis in experimental physics at our institute. Karin’s master thesis work concerned resonant and non-resonant x-ray scattering experiment on strongly correlated electron systems. In particular, Karin’s RIXS experiments on Ca3Ru2O7 were very successful. We are very pleased that Karin will continue within our group as a PhD student. | |
| | Orthorhombic crystal structure typically leads to formation of domains and domain boundaries that are undesirable for many experiments. Detwinning can be done by application of uniaxial pressure. This video shows how a Ca3Ru2O7 crystal is being detwinned. Resulting single crystals were used for ARPES experiments revealing a rotational-symmetry broken Dirac semimetallic electronic structure (arXiv:1911.12163). | |
| | With modern synchrotron and neutron scattering spectroscopy methods, the sheer size of data collection makes quick and efficient analysis and visualization of experimental results a challenging task. Compared to older instruments, modern spectrometers are producing “big data”. Previously reported on this page, PhD student Kevin Kramer has developed an elegant visualization tool for such big spectroscopy data. Although developed for ARPES data, it is applicable to many other areas of science. Here is a video showing how Kevin’s python script can visualize (in real time) time-of-flight neutron scattering data. We conclude by quoting Niels Bech Christensen from DTU-Denmark: “Very impressive, and a huge step forward in visualizing of time-of-flight spectroscopy data. I spent half my PhD looking at such data but never had the opportunity to look at them in a manner as efficient as this.” | |
 | In the week 30.09 – 04.10, PhD student Rina Tazai – from Prof. Kontani’s group (Nagoya University) – visited us. Rina presented her work on superconducting CeCu2Si2 and the hidden order phase in CeB6. From Rina, we got more insight into multipole orderings. A complete list of Rina’s works can be found on this link. | |
 | In between synchrotron experiments, Masafumi received the prestigious High-Temperature Superconductivity Forum young scientist research award at the forum meeting in Nagoya (Japan). This prize recognizes Masafumi’s experimental contributions to both electron- and hole-doped cuprate superconductors. | |
 | Earlier this year, Denys earned his PhD based on ARPES work on the ruthenates that led to two publications (Link Link). Prior to his successful defense, Denys has been awarded a CHF 150k UZH BioTech-MedTech Entrepreneur Fellowship from the Werner-Siemens-Foundation to develop a new type of cryo-sample holder (condenZero) for transmission electron microscopy. | |
| | Doing things from scratch is often an occasion to think about what can be done better, faster or more elegantly. For his PhD project Kevin decided to write his own ARPES analysis software in python. While doing so, he realized that the problem of fast visualization of 3+ dimensional data had already been solved in the medical field. Doctors and surgeons require tools to quickly analyze the multidimensional results of CT and MRI scans. To that end, optimized libraries have already been created. Kevin made use of this fact and adapted the libraries to the needs of ARPES data analysis. The result is the probably fastest ARPES visualization tool to date. With the core code standing, the next steps are the implementation of common analysis routines as well as creation of user-friendly interfaces. To speed up this process and to provide a service to the community, the data is freely available on github and everyone is warmly encouraged to take part in the future development. | |
| | Usually nature allows crystals to peacefully change their symmetry / space-group. Some crystallographic phase transitions, however, have dramatic consequences for the crystal. This is, for example, the case for Ca2-xSrxRuO4 with x<0.2. This video shows pins glued to Ca1.9Sr0.1RuO4 in 1/20 times real time (slow motion). Once the system is cooled through the phase transition, the Ca1.9Sr0.1RuO4 crystals are exploding and the pins are catapulted out into the vacuum chamber. | |
 | Oleh earned his PhD last October (2018) from his work on resonant and non-resonant x-ray scattering experiments on dichalcogenides and cuprate materials. The completion of this PhD work was accelerated due to start of his new job as a postdoctoral beamline scientist at DESY – Hamburg. Today, a central part of his PhD work was published in Nature Communications [Link]. | |
 | Our long-term collaborator Yasmine Sassa has been appointed on a tenure track professorship at Chalmers University of Technology in Gothenburg – Sweden. We wish Yasmine all the best for the formation of this new research group and hope to keep the excellent collaborative spirits. | |
 | Together with co-PI Prof. H. Nojiri (Tohoku University, Sendai, Japan), we got a network grant running for the next three years (2018-2020). Under the title “Quantum Matter Research under Extreme Conditions”, the network aim to carry out scattering experiments on quantum matter in high magnetic field. The grant covers primarily travelling of network members between Europe and Japan. On the European side, the network consists of Prof. H. Rønnow (EPFL), Dr. S. Gerber (PSI), M. von Zimmermann (DESY - Hamburg) and N. B. Christensen (DTU - Copenhagen). In October, master student Karin von Arx (UZH) will be travelling to Japan - SACLA with Dr. Jaewon Choi (UZH) to carry out x-ray diffraction experiments. | |
 | A sequence of three connected ARPES experiments on the cuprates have been published by Christian and Masafumi. First, identification of the dz band and orbital hybridization was obtained in overdoped La2-xSrxCuO4 [Link]. This particular nodal band structure turned out to constitute the first experimental realization of 2D type-II Dirac Fermions [Link]. Finally, the dz band’s proximity to the Fermi level leads to a pronounced Fermi surface kz warping detected directly by soft x-ray ARPES [Link]. These results were presented by Masafumi at the M2S conference in Beijing (August 2018). | |
 | In fall 2017, Kevin Hauser finished his bachelor work concerned with ARPES experiments on La-based cuprates. From this work three manuscripts (Nat. Comm. 9, 972 (2018), arxiv:1804.08019, arxiv:1802.01376) emerged. Following this success, Kevin has been awarded a Zeno-Karl-Schindler grant to carry our his master thesis project at Harvard University within the group of Prof. Jennifer Hofmann. | |
 | Based on her bachelor work carried out at the physics department of National Tsing Hau, Taiwan, Céline Nauer has been awarded a semester prize. During this bachelor project Céline constructed a seeding laser for experiments on myonic hydrogen to determine the proton radius. | |
 | While Christian has ready finished his PhD thesis, Claudia will defend soon. They however both won out-going postdoc fellowships. Claudia is going to the group of Prof. Lanzara at Uni-Berkeley to carrier time- and spin- resolved photoemission studies. Christian decided to join the group of Jenny Hofmann at Harvard and hence will continue with STM experiments. | |
 | In June, Daniel Destraz gave his first invited talk at an international conference (Super Stripes at the Ischia island near Napoli, Italy). Daniel presented his recently published results (Phys. Rev. B 95, 224501) on superconducting fluctuations in NbN films where short-lived Cooper pairs moves in opposite directions to the quasiparticles. | |
 | For decades, the mechanism of Mott phase in Ca2RuO4 has puzzled researchers. This material is a paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling. Progress has been impeded by the lack of knowledge about the low-energy electronic structure. With our recent contribution, we provided-- using angle-resolved photoemission electron spectroscopy -- the band structure of the paramagnetic insulating phase of Ca2RuO4. → Read more | |
 | Each year the Swiss Confederation awards Government Excellence Scholarships to promote international exchange and research cooperation. This year Lakshmi Das is one of the winners of such a PhD grant with the working title: "From exotic superconductivity to insulating quantum matter". Congratulations to Lakshmi. A lot of work is waiting ahead ! | |
| | Denys has been awarded a semester prize for his master thesis that revealed the electronic band in the paramagnetic Mott insulator Ca2RuO4. In addition to the prize, the thesis was also given a distinction. Congratulations to Denys for having successfully accomplished his master within one year. | |
 | More than 50 physicists, from all over Switzerland, joined the topical MaNEP meeting on topological quantum phenomena, at the University of Zurich on November 21-22, 2016. The meeting was held over two days at the Irchel campus of the University of Zurich. It brought together experimentalists and theorists, including PhD students, Postdocs and professors, to discuss recent advances in the field of topological materials. → Read more | |
 | In October Christian Matt and Andrey Sidorenko joined our group as postdocs. Christian has just defended his PhD thesis work dealing with the electronics of high-temperature superconductivity and Andrey has many years of experience with local probe techniques and ultra-low (micro-kelvin) temperature experiments in addition to his PhD in theoretical physics. Welcome to both of them! | |
 | With convincing style Fabio Cossalter defended his Bachelor thesis concerned with angle resolved photoemission spectroscopy data on the Mott insulator Ca2RuO4. This work carried out at the Diamond light source, Oxford. Congratulations to Fabio. | |
 | In a recent publication we demonstrated how charge order in the archetypal high temperature superconductor YBa2Cu3O7-x undergoes a field induced two- to three dimensional transition. Our data provides an explanation as to why an electronic reconstruction has been observed in high magnetic fields. → Read more | |
 | Denys started his fast-track PhD in LQMR in September 2015 after completing his bachelor studies at UZH and six months travel in Asia. With a backgound as Physik Laborant, Denys is going play a vital role in getting our laboratory going. For his PhD research Denys will focus on electronic surface transport. Welcome to Denys. | |
 | The PhD project of Oleh marks the start of the "ERC-SNF" QMAP project funded by the Swiss National Science Foundation. Oleh did his master studies at the Milano Polytechnical School and specialized in STM experiments. For his PhD project, Oleh will be using neutron scattering and synchrotron facilities to study correlated electron materials. | |
 | Summer season is the time when scientists are going to conferences and presenting their most exiting results. In July, LQM member Claudia Fatuzzo was awarded a prize for best young scientist presentation at the Super-Stripe conference held in Erice, Sicily. → Read more |