Ivan Chemakin: Kunst im Labor

Ivan Chemakin: Kunst im Labor, 29.11 - 01.12.2019

Controlling Light by Manipulating Electromagnons

Within some specialised materials, light can appear to move in mysterious ways, rotating around its direction of propagation, and becoming dimmed to different degrees, depending on its direction of travel. Professor Andrei Pimenov and his team at the Vienna University of Technology investigate how these properties are linked to recently discovered quasiparticles named ‘electromagnons’. The team’s work could soon open up new ways to consciously control the propagation of light within these unique solid materials, with numerous exciting technological applications.


We welcome Janek Wettstein

Janek studied physics at Karlsruhe Institute of Technology from 2013 to 2019 where he succesfully performed his master thesis in the Heisenberg Spin-dynamics Group of PD Khalil Zakeri. In his thesis he investigated collective excitations in one monolayer FeSe grown on SrTiO3 using spin-polarized electron energy loss spectroscopy. In July 2019 Janek joined the group as a doctoral candidate.

New Project

EMERGE: Emergent Electrodynamics in Frustrated Magnets

One fascinating consequence of the constrained spin degrees of freedom in certain frustrated magnets is the ability to describe their collective behaviour by emergent gauge fields. Interestingly, this emergent description can be shown to express a novel form electrodynamics on top of the collective magnetic behaviour where new particles such as magnetic monopoles can exist. This project aims to study this emergent behaviour by probing these novel excitations and their dynamics using terahertz radiation.

Creation of magnetic monopole in spin ice

The perfect terahertz beam - thanks to the 3D printer

TU Wien has succeeded in shaping terahertz beams with extremely high precision. All that is needed for this is a simple plastic screen from a 3D printer.

Terahertz radiation can be used for a wide variety of applications and is used today for airport security checks just as much as it is for material analysis in the lab. The wavelength of this radiation is in the millimeter range, meaning that it is significantly larger than the wavelength of visible light. It also requires specialized techniques to manipulate the beams and get them into the right shape. At TU Wien, shaping terahertz beams is now something of a resounding success: with the help of a precisely calculated plastic screen produced on the 3D printer, terahertz beams can be shaped as desired.

(read more) (article) Jan Gospodaric and Andrei Pimenov in the lab

Successful PhD Thesis Defense

Congratulations to our group member and friend Uladzislau Dziom for successfully defending his PhD thesis, "THz spectroscopy of novel spin and quantum Hall systems", supervised by Prof. Dr. A. Pimenov.

PhD defense of Uladzislau Dziom

Using electricity to switch magnetism

At TU Wien, a major step has been taken towards linking electrical and magnetic material properties, which is crucial for possible applications in electronics.

It’s not exactly a new revelation that electricity and magnetism are closely linked. And yet, magnetic and electrical effects have been studied separately for some time now within the field of materials science. Magnetic fields will usually be used to influence magnetic material properties, whilst electrical properties come down to electrical voltage. Then we have multiferroics – a special group of materials that combine the two. In a new development, TU Wien has managed to use electrical fields to control the magnetic oscillations of certain ferrous materials. This has opened up huge potential for computer technology applications, as data is currently transferred in the form of electrical signals but stored magnetically.

(read more) (article) Pimenov Team

3rd Grandmaster PhD Workshop in Physics, 2018 TU Wien

Following the success of previous workshops organized in Augsburg and Budapest, we are pleased to announce the 3rd Grandmaster PhD Workshop in Physics. This year the workshop will be held at TU Wien, from February 19 to 23.

The workshop aims to provide a forum for young scientists to present their results that are of interest to a scientific community, yet in a colloquial atmosphere. MSc, PhD student and post-doc participants can contribute either an oral (25 minutes talk + 5 minutes for discussions) or poster presentation. Through this, the participants can get insight into on-going research projects in the field of solid state physics, and become familiar with related experimental techniques at other contributors’ institutes. In the long term, we hope that this workshop can help initiate bilateral or multilateral research programs.

The highlight of the workshop will be a one-day-symposium entitled From Topology to Superconductivity. Distinquished experts in the field will give tutorial talks covering both the fundamental aspects and potential applications.

We welcome Nadezhda Kostyuchenko

Nadezhda defended his PhD at the Moscow Institute of Physics and Technology (State University), Russia in 2016. In her thesis she studied the influence of the crystal-field and exchange interactions on properties of rare-earth magnetics: iron borates, aluminum borates and intermetallics. Nadezhda joins our group to continuing her research on the theory (analytical and numerical) of magnetic, magnetoelecric and others properties of multiferroics, magnetoelectrics and intermetallics.

We welcome Dávid Szaller

Dávid defended his PhD at the Budapest University of Technology and Economics, Hungary in 2017. In his thesis he studied the low energy optical properties of magnetoelectric multiferroic crystals. One of the most fascinating effect these materials present is directional dichroism, i.e. different absorption of counter-propagating light beams, which David has observed in several multiferroics in the THz frequency regime. Besides the optical experiments, in order to gain a deeper insight into this phenomenon he also carried out group-theoretical and statistical-physical analyses. David joins our group as a PostDoc, continuing his research on the low frequency excitations of multiferroics.

Measured for the first time: direction of light waves changed by quantum effect

The 'quantized magneto-electric effect' has been demonstrated for the first time in topological insulators at TU Wien, which is set to open up new and highly accurate methods of measurement.

A light wave sent through empty space always oscillates in the same direction. However, certain materials can be used to rotate the direction in which the light is oscillating when placed in a magnetic field. This is known as a 'magneto-optical' effect.

After much speculation spanning a long period of time, one variant of this type of effect has now been demonstrated at TU Wien for the first time. Rather than switching the direction of the light wave continually, special materials called 'topological insulators' do so in quantum steps in clearly defined portions. The extent of these quantum steps depends solely on fundamental physical parameters, such as the fine-structure constant. It may soon be possible to measure this constant even more accurately using optical techniques than is currently possible via other methods. The latest findings have now been revealed in the open-access journal 'Nature Communications'.

(read more) (article) Pimenov Team

We welcome Lorenz Bergen

Lorenz studied Physics at TU Wien from 2010 to 2016, completed with a Diploma thesis performed in the group of Prof. Aumayr. There he investigated the nanostructuring of surfaces by swift heavy ion impacts. After working at the Helmholtz-Zentrum Dresden-Rossendorf, Lorenz came back to Vienna in 2017 and joined the group as a PhD-Student.

We welcome Evan Constable

Evan is an Australian researcher with a background in terahertz spectroscopy. In 2014, he completed his PhD at the University of Wollongong, Australia where he focused on spectroscopy of magnetic materials. During his studies, he developed a keen interest into the complementary nature of terahertz and neutron spectroscopic techniques. This interest brought him to Grenoble, France, where he undertook a postdoc position with the CNRS at Institut Néel from 2015 to 2017. Working closely with researchers at the SOLEIL synchrotron and ILL reactor, Evan continued to develop projects that brought together complementary terahertz and neutron scattering experiments on frustrated magnetic systems. Evan now joins the solid-state spectroscopy group as a postdoctoral researcher. His primary research interests remain in the fields of terahertz spectroscopy, frustrated magnetism and multiferroics.

We welcome Jan Gospodarič

Jan joined the group in the beginning of 2017 as a doctoral candidate. He previously studied physics at University of Ljubljana, Slovenia from 2010 to 2016, a study he ended with a successful Master's thesis project at the Jožef Stefan Institute in a research group of prof. Dragan Mihailović. His thesis examined the optical spectroscopy of a hidden state in 1T-TaS2 in visible regime.

We welcome Lukas Weymann

Lukas studied from 2011 to 2016 physics at the Leibniz University in Hannover. He wrote his master thesis at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in the independent research group of Dr. Holger Pletsch. His thesis was based on the gamma-ray timing of an extreme black widow binary pulsar.

New PostDoc position

There is a new PostDoc position available in the area of optical and infrared spectroscopy.

Successful PhD Thesis Defense

Congratulations to our group member and friend Markus Schiebl for successfully defending his PhD thesis, "Dielectric spectroscopy at the spin-driven ferroelectric phase transition in chiral multiferroic DyMnO3", supervised by Prof. Dr. A. Pimenov.

PhD defense of Markus Schiebl

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