News and posts

20.05.2020 – 800 participants on the first Online SPICE-SPIN+X seminar by Tomas Jungwirth!

We are delighted to see the enormous interest in the new Online SPICE-SPIN+X Seminars. We had 500 participants in Zoom (to capacity) and over 300 watching life on YouTube. Tomas Jungwirth gave the inaugural seminar on Antiferromagnetic spintronics: from memories to ultra-fast optics and topological transport. His talk is available on the SPICE YouTube Channel and can also be reached to the direct link here.

 

To receive by e-mail the Zoom Meeting log-in information and the announcements, please sign up to the seminars e-mail list (no further announcements on the on-line seminars will be sent by the news-from-spice mailing list). You can click here for the e-mail list sign-up form or find it directly at the SPICE-SPIN+X Seminars website.

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18.05.2020 – New Online SPICE-SPIN+X seminar series

In the time of physical distancing, it is more important than ever to remain close socially and scientifically. The Spin Phenomena Interdisciplinary Center SPICE and the Collaborative Research Center SPIN+X have joined forces to start a weekly condensed matter seminar series with an emphasis on spin and topological physics.

The talks will be given via Zoom and live streamed on the SPICE YouTube Channel, with most of them also available afterwards on the channel.

To receive by e-mail the Zoom Meeting log-in information and the announcements, please sign up to the seminars e-mail list (no further announcements on the on-line seminars will be sent by the news-from-spice mailing list). You can click here for the e-mail list sign-up form or find it directly at the SPICE-SPIN+X Seminars website. To listen to the talk through the livestreaming, simply go to the SPICE YouTube Channel at the time of the seminar. Attendance is of course free.

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On-line SPICE-SPIN+X Seminars

On-line Seminar: 27.05.2020 - 15:00 (CET)

Half-integer charge transfer by Majorana edge modes

Carlo Beenakker, Leiden University

A Josephson junction in a chiral p-wave superconductor can inject a charge e/2 into a normal-metal contact, carried by chiral Majorana edge modes. We address the question whether this half-integer charge is a sharp observable, without quantum fluctuations. Because the Majorana modes are gapless, they support charge fluctuations in equilibrium at zero temperature. But we find that the excess noise introduced out of equilibrium by the e/2 charge transfer vanishes. We discuss a strategy to reduce the equilibrium fluctuations, by means of a heavy-tailed time-dependent detection efficiency, to achieve a fully noiseless half-integer charge transfer.

 

 

PDF file of the talk available here

This seminar is now  directly linked here and in the SPICE YouTube Channel. Please subscribe to receive the Zoom log-in information. 

On-line SPICE-SPIN+X Seminars

On-line Seminar: 20.05.2020 - 15:00 (CET)

Antiferromagnetic spintronics: from memories to ultra-fast optics and topological transport

Tomas Jungwirth, Institute of Physics of the Science Academy of the Czech Republic

Fifty years ago, Louis Néel pointed out in his Nobel lecture that while interesting from theoretical viewpoint, antiferromagnets did not seem to have any applications. Indeed, the alternating directions of magnetic moments on individual atoms and the resulting zero net magnetization have made antiferromagnets hard to control by the magneto-recording tools common in ferromagnets. This has hindered both the research and utility of these abundant magnetic materials. Replacing magnetic fields with modern spintronic tools has recently prompted renewed research interest in antiferromagnets. Experimental studies in antiferromagnets have successfully adapted concepts from ferromagnetic spintronics for storing, writing, and reading information. Besides electronic memory devices, antiferromagnetic spintronics has also demonstrated its utility in the research of ultra-fast optical manipulation of magnets or topological magneto-transport. In the talk we will give an overview of these diverse areas of the emerging field of antiferromagnetic spintronics.

PDF file of the talk available here

This seminar is  directly linked here and in the SPICE YouTube Channel.

Please subscribe to receive the Zoom log-in information.

09.12.2019 – Elastic Tuning and Response of Electronic Order

Elastic Tuning and Response of Electronic Order

New physical phenomena have emerged from a particularly strong coupling between a materials’ elasticity and its symmetry-broken electronic quantum phases. Examples are reversible superelasticity with large recoverable strain in iron-based materials, strong nonlinear elastic response with violation of Hooke’s law and critical elasticity in pressurized organic charge-transfer salts, a doubling of the superconducting transition temperature in strained strontium ruthenate, strain-induced charge order in cuprate superconductors, as well as nematicity in iron-based superconductors. Static and dynamic strain manipulation has emerged as a new knob to tune and shape a material’s electronic properties.

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Program - Elastic Tuning and Response of Electronic Order

 

 

 

 

Monday, December 9th

Morning Session 

08:50 – 09:20 Registration
09:20 – 09:30 Opening Remarks
09:30 – 10:20 Ian FISHER, Stanford University
Feeling the strain: tuning the critical temperature of electronic nematic phases
10:30 – 10:50 Coffee Break
10:50 – 11:20 Anna BÖHMER, KIT
Tuning magnetism in iron-based superconductors
11:30 – 12:00 Bernd BÜCHNER, IFW
Strain dependent transport and nematicity in Fe based superconductors
12:00 – 14:30 Lunch Break

Afternoon Session

14:40 – 15:10 Elena GATI, IOWA State University
Effect of hydrostatic pressure and uniaxial stress on the competing phases in iron-based superconductors
15:20 – 15:50 Suguru HOSOI, Osaka University
Elastoresistance measurements in nematic superconductors
16:00 – 16:30 Collin BROHOLM, Johns Hopkins University
Magneto-elasticity in Fragile Magnets
18:00 – 19:30 Dinner

Tuesday, December 10th

Morning Session

09:00 – 09:50 Steven Allan KIVELSON, Stanford University
Nematicity, strain, and disorder: Universal features from statistical mechanics
10:00 – 10:30 Heejae KIM, Max Planck Institute for Polymer Research
Nonlinear spectroscopic study of electron-phonon coupling
10:30 – 10:50 Coffee Break & Poster Session
10:50 – 11:20 Rafael FERNANDES, University of Minnesota
Contrasting nematicity in rigid lattices and moiré superlattices
11:30 – 12:00 Kristin KLIEMT, University Frankfurt
Advanced methods for single crystal growth of Eu- and Yb-based intermetallic systems
12:00 – 14:30 Lunch Break & Poster Session

Afternoon Session

14:30 – 15:00 Stephen ROWLEY, Cambridge
Strong electron pairing in ferroelectric superconductors
15:10 – 15:40 Philipp GEGENWART, University of Augsburg
Thermal expansion signatures of the quadrupolar Kondo effect
15:50 – 16:20 Marcel SCHRODIN, KIT
Nanoscale sensing with single spins in diamond
16:20 – 17:30 Poster Session
18:00 – 19:30 Dinner

Wednesday, December 11th

Morning Session

09:00 – 09:50 Michael LANG, University of Frankfurt
Molecular metals – test ground for correlated electrons in a compressible lattice
10:00 – 10:30 Clifford HICKS, MPG
Superconductors and magnets under uniaxial stress
10:30 – 10:50 Coffee Break 
10:50 – 11:20 Helen GOMONAY, JGU
Elastic manipulation of antiferromagnetic domain structure
11:30 – 12:00 Kristin WILLA, KIT
Evidence for nematic superconductivity in the superconducting doped topological insulators NbxBi2Se3 and SrxBi2Se3
12:00 – 14:30 Lunch 

Afternoon Session 

14:30 – 15:00 Stuart BROWN, UCLA
Unconventional superconductivity in Sr2RuO4, probed under stressed conditions
15:10 – 15:40 Taner YILDIRIM, NIST
Pressure and Strain Control of Crystal Symmetry, Fermi Surface Reconstruction and Superconductivity in Weyl semimetal MoTe2
15:50 – 16:00 Closing Remarks

 

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12.11.2019 – Novel Electronic and Magnetic Phases in Correlated Spin-Orbit Coupled Oxides

Novel Electronic and Magnetic Phases in Correlated Spin-Orbit Coupled Oxides

The interplay between spin, orbit and electron correlation has emerged as a new paradigm in contemporary condensed matter physics and represents a rich playground for the realization of novel quantum state of matters with exotic electronic and magnetic properties including Dirac-Mott insulators, Lifshitz/Slater phases, Multipolar and Kitaev model magnetism, unconventional superconductivity and topological physics.

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15.10.2019 – Molecular Electro-Opto-Spintronics

Molecular Electro-Opto-Spintronics

Molecular electronics originally promised miniaturization of molecular devices using Nature’s smallest building blocks to allow for novel electronic function by simply altering the chemical structure of the molecular component. Molecular electronics has evolved towards a complementary technology to silicon-based electronics, providing functionalities not possible with classical electronic devices. After more than 40 years of experiments, it remains a challenge to rationally design molecule-electrode junctions due the complex interplay between electronic structure and the chemical/supramolecular arrangement of the interfaces. Unlike traditional CMOS electronics, comprehensive design rules for molecular junctions are not available yet. Only bits and pieces have been published scattered across disciplines, including interface engineering, supramolecular chemistry, surface science, computational science, physics, chemistry, optics, biology and micro/nanofabrication.

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07.10.2019 – Antiferromagnetic Spintronics

Antiferromagnetic Spintronics: from topology to neuromorphic computing

The new field of antiferromagnetic spintronics focuses on making antiferromagnets active elements of spintronic devices. The higher complexity of the ordered phase and parameter space in antiferromagnets have given rise to new avenues of basic research that range from topological quasiparticle dynamic manipulation, multipole order effects, ultra-fast dynamics, and even applications towards neuromorphic computing and IoT.

The new field is of interest to the strongly correlated effects community and the community focused on topological matter. It has connected to the current ferromagnetic spintronics research by creating entirely new ways of rethinking spin phenomena in antiferromagnets, while benefiting from the pioneering works in antiferromagnetic materials.

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30.09.2019 – Young Research Leader Group Workshop

YRLGW: Topomagnetism Is Coming: Relativity and Correlations in Topological Magnets

Remarkable advances in strongly correlated and relativistic condensed matter physics have been made over the past decade by these largely non-interacting communities. Interestingly, their attention recently focused on the same grand challenges such as room-temperature quantum chiral edge modes, topological superconductivity, or topological computation.

The research of nonmagnetic materials culminated in predicting that approximately one third of them exhibit topological electronic structure. In contrast, the investigation of topological magnets is progressing at much slower pace albeit time-reversal symmetry broken topological phases demand magnetic order. For a long time, low-dimensional topological systems were anticipated to be naturally incompatible with robust magnetism. However, recent theoretical and experimental efforts have revealed low-dimensional as well as 3D topological insulators and Weyl semimetal magnets. The relativistic phenomena, e.g. the spin Hall, quantum spin Hall, or magnetic spin-Hall effect, were originally predicted within the single-particle picture. However, realistic predictions of magnetic materials, requires inclusion of the electronic correlations. Conversely, the correct description of strongly correlated magnets with high atomic numbers needs to include spin-orbit coupling phenomena.

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