On-line SPICE-SPIN+X Seminars

On-line Seminar: 17 June 2020 - 15:00 (CET)

Coherent Sub-Terahertz Spin Pumping from an Insulating Antiferromagnet

Enrique del Barco, University of Central Florida

Emerging phenomena, such as the spin-Hall effect (SHE), spin pumping, and spin-transfer torque (STT), allow for interconversion between charge and spin currents and the generation of magnetization dynamics that could potentially lead to faster, denser, and more energy efficient, non-volatile memory and logic devices. Present STT-based devices rely on ferromagnetic (FM) materials as their active constituents. However, the flexibility offered by the intrinsic net magnetization and anisotropy for detecting and manipulating the magnetic state of ferromagnets also translates into limitations in terms of density (neighboring elements can couple through stray fields), speed (frequencies are limited to the GHz range), and frequency tunability (external magnetic fields needed). A new direction in the field of spintronics is to employ antiferromagnetic (AF) materials. In contrast to ferromagnets, where magnetic anisotropy dominates spin dynamics, in antiferromagnets spin dynamics are governed by the interatomic exchange interaction energies, which are orders of magnitude larger than the magnetic anisotropy energy, leading to the potential for ultrafast information processing and communication in the THz frequency range, with broadband frequency tunability without the need of external magnetic fields.

PDF file of the talk available here

I will present evidence of sub-terahertz coherent spin pumping at the interface of a uniaxial insulating antiferromagnet MnF2 and platinum thin films, measured by the ISHE voltage signal arising from spin-charge conversion in the platinum layer. The ISHE signal depends on the chirality of the dynamical modes of the antiferromagnet, which is selectively excited and modulated by the handedness of the circularly polarized sub-THz irradiation (see figure). Contrary to the case of ferromagnets, antiferromagnetic spin pumping exhibits a sign dependence on the chirality of dynamical modes, allowing for the unambiguous distinction between coherent spin pumping and the thermally-driven, chirality-independent spin Seebeck effect. Our results open the door to the controlled generation of coherent pure spin currents with antiferromagnets at unprecedented high frequencies.

This work has been primarily supported by the Air Force Office of Scientific Research under Grant FA9550-19-1-0307.


  • Priyanka Vaidya, Sophie A. Morley, Johan van Tol, Yan Liu, Ran Cheng, Arne Brataas, David Lederman, and Enrique del Barco, Subterahertz spin pumping from an insulating antiferromagnet, Science 368, 160-165 (2020)



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On-line SPICE-SPIN+X Seminars

On-line Seminar: 10 June 2020 - 15:00 (CET)

Magnetic tunnel junctions and magnetic logic circuits driven by spin-orbit torques

Pietro Gambardella,

Department of Materials, ETH Zurich, Switzerland

Current-induced spin-orbit torques (SOTs) enable the switching of magnetic tunnel junctions (MTJs) in nonvolatile magnetic random access memories as well as the all-electrical operation of magnetic logic circuits based on domain wall manipulation. In this talk, I will present time-resolved measurements of magnetization reversal driven by SOTs in 3-terminal MTJ devices and discuss how the combination of SOT, spin transfer torque, and voltage control of magnetic anisotropy leads to reproducible sub-ns magnetization reversal with a very narrow spread of the switching time distributions [1]. Further, I will show how SOTs and the chiral coupling between neighbouring magnetic domains induced by the interfacial Dzyaloshinskii–Moriya interaction [2] allow for realizing an electrically-driven domain-wall inverter. Starting from this basic building block, it is possible to fabricate reconfigurable NAND and NOR logic gates, and therefore a complete family of logic gates, which perform operations with current-induced domain-wall motion [3]. Opportunities for scalable all-electric magnetic memories and memory-in-logic applications will be discussed.

PDF file of the talk available here


  • [1] Single-shot dynamics of spin-orbit torque and spin transfer torque switching in 3-terminal magnetic tunnel junctions, E. Grimaldi, V. Krizakova, G. Sala, F. Yasin, S. Couet, G. S. Kar, K. Garello and P Gambardella, Nat. Nanotech. 15, 111 (2020).
  • [2] Chirally Coupled Nanomagnets, Z. Luo, T. Phuong Dao, A. Hrabec, J. Vijayakumar, A. Kleibert, M. Baumgartner, E. Kirk, J. Cui, T. Savchenko, G. Krishnaswamy, L. J. Heyderman, and P. Gambardella, Science 363, 1435 (2019).
  • [3] Current-driven magnetic domain-wall logic, Z. Luo, A. Hrabec, T. P. Dao, G. Sala, S. Finizio, J. Feng, S. Mayr, J. Raabe, P. Gambardella, L. J. Heyderman, Nature 579, 214 (2020).

Figure 1. a, Scanning electron microscope image of a 3-terminal magnetic tunnel junction device with injection electrodes for spin-orbit torque (SOT) and spin transfer torque (STT) switching. b, Detail of the magnetic tunnel junction pillar and W current line. c, Electrical setup for the time-resolved measurements of the tunneling magnetoresistance during SOT and/or STT switching. d, Examples of ten different single-shot switching events induced by spin-orbit torques. Adapted from [1].


On-line SPICE-SPIN+X Seminars

On-line Seminar: 3 June 2020 - 15:00 (CET)

Probing ultrafast spin transport with terahertz electromagnetic pulses

Tobias Kampfrath, Freie Unversität Berlin and Fritz Haber Institute of the Max Planck Society, Berlin

Transport of spins is often driven by heat gradients and electric fields. To probe the initial elementary steps which lead to the formation of spin currents, we need to launch and measure transport on femtosecond time scales. This goal is achieved by employing both ultrashort optical and terahertz electromagnetic pulses. We illustrate our experimental approach by several examples including the spin Seebeck effect (see figure) and anisotropic magnetoresistance.



  • [1] Seifert et al., Nature Comm. 9, Article number: 2899 (2018)
  • [2] Seifert et al., J. Phys. D: Appl. Phys. 51, 364003 (2018)

PDF file of the talk available here

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. 

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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20.12.2017 – Job offer: PhD Position in Spintronics in the Institute of Physics at the Johannes Gutenberg-Universität Mainz


PhD Position in Spintronics

Johannes Gutenberg-Universität Mainz, Germany


We are pleased to announce the opening of two PhD positions in theoretical condensed matter in the Institute of Physics at the Johannes Gutenberg-Universität Mainz to work with the spintronics theory groups INSPIRE (Jairo Sinova) and TWIST (Karin Everschor- Sitte) on topics such as antiferromagnetic spintronics, skyrmions, and topological matter. The physics institute and the Spin Phenomena Interdisciplinary Center (SPICE) provides a stimulating environment due to an active workshop program and a broad range of research activities.

The prospective group member must hold a MSc or equivalent diploma. A background in theoretical techniques in condensed matter physics is required. Candidates interested and/or experienced in spintronics, magnetization dynamics, the physics of antiferromagnetics or skyrmions, and micromagnetic modelling are highly suited for this opportunity. Programming experience is desired.

Further information can be found on the websites: or

Johannes Gutenberg-Universität Mainz is an equal opportunity, affirmative actions employer in compliance with German disability laws. Women and persons with disabilities are encouraged to apply.

Review of applications begins immediately and will continue until the position is filled. Interested applicants should send a curriculum vitae, a list of publications, and at least two letters of recommendation to When sending applications please use the subject line “Spintronics PhD position application”.



Prof. Jairo Sinova
Head of the group INSPIRE
Director of SPICE

Dr. Karin Everschor-Sitte
Head of Emmy Noether Research Group TWIST
Scientific Coordinator of SPICE

Johannes Gutenberg-Universität Mainz FB 08 – Institut für Physik Staudingerweg 7
55128 Mainz

04.07.2016 – SPICE Team and INSPIRE Group Workshop in Sörgenloch


On July 4th and 5th the SPICE team and INSPIRE group had an internal group workshop in the picturesque village of Sörgenloch close to Mainz. In the nice atmosphere of Schloss Sörgenloch the SPICE team and INSPIRE group focused on team building processes and internal working strategies. The group also used the occasion to welcome Ulrike Ritzmann, as well as Bertrand Dupé and Marie Böttcher, who will join the group in October 2016. After a very successful first day, the group enjoyed the food and a variety of local wines served on the Schloss Sörgenloch terrace in the evening. On the second day of the workshop the group worked on presentation techniques and communication skills under the guidance of two coaches from an improvisational theater. We thank the participants for two beautiful and very successful days in Sörgenloch..

17.06.2016 – Young Research Leaders Group Workshop: New Paradigms in Dirac-Weyl Nanoelectronics

With the impending end of traditional Si based electronics due to Moore's law limitations, the need for novel approaches to next generation device design is not only apparent, but has become a popular interdisciplinary research topic. From research in fabrication engineering and device architectural design to devices based on intrinsically different physics, there is ample room for research from physics, chemistry, and engineering perspectives. From June 13th to 17th, our  SPICE Young Research Leaders Workshop was held to approach the problem from a primarily materials perspective aiming to use external stimuli such as classical gating, ionic liquid gating, optical excitation, magnetic field control, strain, etc. to cause large physical property changes in Dirac and Weyl materials due to their unique, sensitive and modifyable Fermi surfaces. Together with co-organizer Jairo Sinova, the organizers Mazhar Ali and Binghai Yan brought together 22 young experts in theoretical and experimental physics, solid state chemistry, and electrical engineering in a multi-disciplinary collaborative effort to quickly bring the exciting new physics of Dirac and Weyl materials to practical application. Through the foundations laid in this workshop, we hope to spark a new field of electronics, discover new materials, new properties, new physics, and possibly create devices based on changing between fundamental states of matter.

For videos of the talks and further information, visit the workshop home page.


20.05.2016 – SPICE Workshop: Quantum Acoustics – Surface Acoustic Waves meets Solid State Qubits

This week, SPICE hosted a Workshop boosting the new field of Quantum Acoustics‐ a phonon analogue of quantum optics on chip – where single phonons in the form of high‐frequency surface acoustic waves (SAWs) propagate in acoustic waveguides coupling remote qubits. The team of organisers consisted of Göran Johansson (Chalmers, Sweden), Christopher Bäuerle (CNRS, France), Paulo Santos (PDI, Germany) and Floris Zwanenburg (Twente, Netherlands). They brought together three scientific communities which have not interacted substantially before, i.e. Surface Acoustic Waves, Solid State Spin Qubits and Superconducting Qubits. In the beautiful location of Schloss Waldthausen, fifty-two international scientists used talks, discussions and a poster session to explore contact points and potential synergies for these three fields. We thank the organizers and all participants for a successful workshop.

For videos of the talks and further information, visit the workshop home page.