In this project, we investigate the coupling of the spin degree of freedom with electronic degrees of freedom across interfaces in ferromagnetic multilayers on the ultrafast time scale. For this purpose, we consider the excitation of the ferromagnetic material by a femtosecond laser pulse. The so created spin-polarized electrons with large energies respond to the applied field which is reflected in the longitudinal and transverse transport coefficients. We consider mainly the energy-dependent transversal transport properties, that are related to the anomalous and the spin Hall effect. In particular, we are interested in the time and spatial dependence of the charge- and spin-current distribution with respect to the interface. On the other hand, we investigate timedependent spin currents that are produced by the spin Hall effect if a THz electric field is applied to the nonmagnetic metal layer. Propagation of this spin current into the ferromagnetic layer causes a spin-transfer torque on the magnetization. Based on an ab initio description in combination with a semi-classical Boltzmann theory we aim at understanding the charge and spin current distributions on nanometer length scales and ultrafast time scales.

Publications (2nd Funding Period 2022 - 2025)

• Enhanced magnetic dichroism in darkfield UV photoemission electron microscopy
  M. Paleschke, D. Huber, F. Wührl, C.-T. Chiang, F. O. Schumann, J. Henk, and W. Widdra
  Phys. Rev. B, in press (2025) - DOI: 10.1103/klc4-lk7g

• Multifunctional steep-slope spintronic transistors with spin-gapless-semiconductor or spin-gapped-metal electrodes
  E. Şaşıoğlu, P. Bodewei, N. F. Hinsche, and I. Mertig
  Phys. Rev. Applied 23, 044022 (2025) - DOI: 10.1103/PhysRevApplied.23.044022
• Spin gapped metals: A novel class of materials for multifunctional spintronic devices
  E. Şaşıoğlu, M. Tas, S. Ghosh, W. Beida, B. Sanyal, S. Blügel, I. Mertig, and I. Galanakis
  J. Magn. Magn. Mater. 615, 172792 (2025) - DOI: 10.1016/j.jmmm.2025.172792

• Computational design of tunnel diodes with negative differential resistance and ultrahigh peak-to-valley current ratio based on two-dimensional cold metals: The case of Nb⁢Si₂⁢N₄/Hf⁢Si₂⁢N₄/Nb⁢Si₂⁢N₄ lateral heterojunction diode
  P. Bodewei, E. Şaşıoğlu, N.F. Hinsche, and I. Mertig
  Phys. Rev. Applied 22, 014004 (2024)   - DOI: 10.1103/PhysRevApplied.22.014004

• Ultrafast orbital Hall effect in metallic nanoribbons
  O. Busch, F. Ziolkowski, B. Göbel, I. Mertig, and J. Henk  
  Phys. Rev. Res. 6, 013208 (2024)   - DOI: 10.1103/PhysRevResearch.6.013208
• Circular motion of noncollinear spin textures in Corbino disks: Dynamics of Néel- versus Bloch-type skyrmions and skyrmioniums
  I. R. de Assis, I. Mertig, and B. Göbel  
  Phys. Rev. B 110, 064404 (2024)   - DOI: 10.1103/PhysRevB.110.064404

• Boosting the Edelstein effect of two-dimensional electron gases by ferromagnetic exchange
  G. Lazrak, B. Göbel, A. Barthélémy, I. Mertig, A. Johansson, and M. Bibes  
  Phys. Rev. Res. 6, 023074 (2024)  - DOI: 10.1103/PhysRevResearch.6.023074

• Electrical activity of topological chiral edge magnons
  R. R. Neumann, J. Henk, I. Mertig, and A. Mook  
  Phys. Rev. B 109, L180412 (2024)  - DOI: 10.1103/PhysRevB.109.L180412

• Magnetic dichroism in darkfield UV photoemission electron microscopy 
  M. Paleschke, D. Huber, F. Wührl, C.-T. Chiang, F. O. Schumann, J. Henk, and W. Widdra 
  Phys. Rev. Lett. submitted, (2024) - DOI: 10.48550/arXiv.2409.04771

• Ultrafast dynamics of electrons excited by femtosecond laser pulses: Spin polarization and spin-polarized currents
  O. Busch, F. Ziolkowski, I. Mertig, and J. Henk
  Phys. Rev. B 108, 184401 (2023) - DOI: 10.1103/PhysRevB.108.184401
• Ultrafast dynamics of orbital angular momentum of electrons induced by femtosecond laser pulses: Generation and transfer across interfaces
  O. Busch, F. Ziolkowski, I. Mertig, and J. Henk
  Phys. Rev. B 108, 104408 (2023) - DOI: 10.1103/PhysRevB.108.104408

• Biskyrmion-based artificial neuron
  I. R. de Assis, I. Mertig, and B. Göbel
  Neuromorph. Comput. Eng. 3, 014012 (2023) - DOI: 10.1088/2634-4386/acb841

• Spin-polarized two-dimensional electron/hole gas at the interface of nonmagnetic semiconducting half-Heusler compounds: Modified Slater-Pauling rule for half-metallicity at the interface 
  E. Gürbüz, S. Ghosh, E. Şaşıoğlu, I. Galanakis, I. Mertig, and B. Sanyal 
  Phys. Rev. Mater. 7, 054405 (2023)  - DOI: 10.1103/PhysRevMaterials.7.054405
• First-principles prediction of energy bandgaps in 18-valence electron semiconducting half-Heusler compounds: Exploring the role of exchange and correlation 
  E. Gürbüz, M. Tas, E. Şaşıoğlu, I. Mertig, B. Sanyal, and I. Galanakis 
  J. Appl. Phys. 134, 205703 (2023)  - DOI: 10.1103/10.1063/5.0178165

• Generation of out-of-plane polarized spin current by spin swapping
  B. K. Hazra, B. Pal, J.-C. Jeon, R. R. Neumann, B. Göbel, B. Grover, H. Deniz, A. Styervoyedov, H. Meyerheim, I. Mertig, S.-H. Yang, and S. S. P. Parkin
  Nat. Commun. 14: 4549  (2023) - DOI: 10.1038/s41467-023-39884-6

• Electronic band structure of superconducting KTaO₃ (111) interfaces 
  S. Mallik, B. Göbel, H. Witt, L. M. Vicente-Arche, S. Varotto, J. Bréhin, G. Ménard, G. Saïz, D. Tamsaout, A. F. Santander-Syro, F. Fortuna, F. Bertran, P. Le Fèvre, J. Rault, I. Boventer, I. Mertig, A. Barthélémy, N. Bergeal, A. Johansson, and M. Bibes
  APL Mater. 11, 121108 (2023)  - DOI: 10.1063/5.0169750

• Atomic displacements enabling the observation of the anomalous Hall effect in a non-collinear Antiferromagnet 
  B. H. Rimmler, B. K. Hazra, B. Pal, K. Mohseni, J. M. Taylor, A. Bedoya-Pinto, H. Deniz, M. Tangi, I. Kostanovskiy, C. Luo, R. R. Neumann, A. Ernst, F. Radu, I. Mertig, H. L. Meyerheim, and S. S. P. Parkin 
  Adv. Mater. 35, 2209616 (2023) - DOI: 10.1002/adma.202209616

• Theoretical prediction of semiconductor-free negative differential resistance tunnel diodes with high peak-to-valley current ratios based on two-dimensional cold metals 
  E. Sasioglu and I. Mertig 
  ACS Appl. Nano Mater. 6, 3758 (2023)  - DOI: 10.1021/acsanm.2c05478

• Ultrafast spin dynamics: complementing theoretical analyses by quantum state measures 
  F. Ziolkowski, O. Busch, I. Mertig, and J. Henk 
  J. Phys.: Condens. Matter 35, 125501 (2023)  - DOI: 10.1088/1361-648X/acb479

• Setting of the magnetic structure of chiral kagome antiferromagnets by a seeded spin-orbit torque
  B. Pal, B. K. Hazra, B. Göbel, J-C. Jeon, A. K. Pandeya, A. Chakraborty, O. Busch, A. K. Srivastava, H. Deniz, J. M. Taylor, H. Meyerheim, I. Mertig, S-H. Yang, and S. S. P. Parkin
  Sci. Adv. 8, eabo5930 (2022) - DOI: 10.1126/sciadv.abo5930

• Atomic scale control of spin current transmission at interfaces 
  M. A. Wahada, E. Şaşıoğlu, W. Hoppe, X. Zhou, H. Deniz, R. Rouzegar, T. Kampfrath, I. Mertig, S. S. P. Parkin, and G. Woltersdorf 
  Nano Lett. 22, 3539 (2022)  - DOI: 10.1021/acs.nanolett.1c0435

Publications (1^st Funding Period 2018 - 2021)

• Colossal topological Hall effect at the transition between isolated and lattice-phase interfacial skyrmions 
  M. Raju, A. P. Petrović, A. Yagil, K. S. Denisov, N. K. Duong, B. Göbel, E.Şaşıoğlu, O. M. Auslaender, I. Mertig, I. V. Rozhansky, and C. Panagopoulos  
  Nat. Commun. 12: 2758 (2021)  - DOI: 10.1038/s41467-021-22976-6

• Broadband terahertz probes of anisotropic magnetoresistance disentangle extrinsic and intrinsic contributions 
  L. Nadvorník, M. Borchert, L. Brandt, R. Schlitz, K. A. de Mare, K. Výborný, I. Mertig, G. Jakob, M. Kläui, S. T. B. Goennenwein, M. Wolf, G. Woltersdorf, and T. Kampfrath
  Phys. Rev. X 11, 021030 (2021)  - DOI: 10.1103/PhysRevX.11.021030

• Ultrafast spin dynamics in inhomogeneous systems: a density-matrix approach applied to Co/Cu interfaces 
  F. Töpler, J. Henk, and I. Mertig
  New J. Phys. 23, 033042 (2021)  - DOI: 10.1088/1367-2630/abe72b

• Spin and orbital Edelstein effects in a two-dimensional electron gas: Theory and application to SrTiO₃ interfaces 
  A. Johansson, B. Göbel, J. Henk, M. Bibes, and I. Mertig 
  Phys. Rev. Res. 3, 0132275 (2021)  - DOI: 10.1103/PhysRevResearch.3.013275

• Beyond skyrmions: Review and perspectives of alternative magnetic quasiparticles 
  B. Göbel, I. Mertig, and O. A.Tretiakov 
  Phys. Rep. 895, 1 (2021)  - DOI: 10.1016/j.physrep.2020.10.001

• Skyrmion ratchet propagation: utilizing the skyrmion Hall effect in AC racetrack storage devices 
  B. Göbel and I. Mertig 
  Sci. Rep. 11 : 3020 (2021)  - DOI: 10.1038/s41598-021-81992-0

• First principles design of Ohmic spin diodes based on quaternary Heusler compounds 
  T. Aull, E. Şaşıoğlu, and I. Mertig 
  Appl. Phys. Lett. 118, 052405 (2021)  - DOI: 10.1063/5.0037085

• Terahertz spin-to-charge conversion by interfacial skew scattering in metallic bilayers
  O. Gueckstock, L. Nádvorník, M. Gradhand, T. S. Seifert, G. Bierhance, R. Rouzegar, M. Wolf, M. Vafaee, J. Cramer, M. A. Syskaki, G. Woltersdorf, I. Mertig, G. Jakob, M. Kläui, and T. Kampfrath
  Adv. Mater. 33, 2006281 (2021) - DOI: 10.1002/adma.202006281

• Evolution and competition between chiral spin textures in nanostripes with D-2d symmetry 
  J. Jena, B. Göbel, V. Kumar, I. Mertig, C. Felser, and S. S. P. Parkin
  Sci Adv. 6 : eabc0723 (2020)  - DOI: 10.1126/sciadv.abc0723

• Topological Hall signatures of two chiral spin textures hosted in a single tetragonal inverse Heusler thin film 
  P. K. Sivakumar, B. Göbel, E. Lesne, A. Markou, J. Gidugu, J. M. Taylor, H. Deniz, J. Jena, C. Felser, I. Mertig, and S. S. P. Parkin 
  ACS Nano 14, 13463 (2020) - DOI: 10.1021/acsnano.0c05413

• Impact of crystalline anisotropy on the extrinsic spin Hall effect in ultrathin films 
  C. Herschbach, D. V. Fedorov, M. Gradhand, and I. Mertig 
  Phys. Rev. B 102, 104421 (2020)  - DOI: 10.1103/PhysRevB.102.104421

• Orbital magnetic moment of magnons 
  R. R. Neumann, A. Mook, J. Henk, and I. Mertig 
  Phys. Rev. Lett. 125, 117209 (2020)  - DOI: 10.1103/PhysRevLett.125.117209

• Unconventional charge–spin conversion in Weyl-semimetal WTe₂
  B. Zhao, B. Karpiak, D. Khokhriakov, A. Johansson, A. Md. Hoque, X. Xu, Y. Jiang, I. Mertig, and S. P. Dash 
  Adv. Mater. 32, 2000818 (2020)  - DOI: 10.1002/adma.202000818

• Half-metal–spin-gapless-semiconductor junctions as a route to the ideal diode 
  E. Şaşıoğlu, T. Aull, D. Kutschabsky, S. Blügel, and I. Mertig 
  Phys. Rev. Appl. 14, 014082 (2020) - DOI: 10.1103/PhysRevApplied.14.014082

• Microscopic origin of the anomalous Hall effect in noncollinear kagome magnets 
  O. Busch, B. Göbel, and I. Mertig
  Phys. Rev. Res. 2, 033112 (2020)  - DOI: 10.1103/PhysRevResearch.2.033112

• Topological Hall signatures of magnetic hopfions
  B. Göbel, C. A. Akosa, G. Tatara, and I. Mertig 
  Phys. Rev. Res. 2, 013315 (2020)  - DOI: 10.1103/PhysRevResearch.2.013315

• Determining the Rashba parameter from the bilinear magnetoresistance response in a two-dimensional electron gas 
  D. C. Vaz, F. Trier, A. Dyrdał, A. Johansson, K. Garcia, A. Barthélémy, I. Mertig, J. Barnaś, A. Fert, and M. Bibes 
  Phys. Rev. Mater. 4, 071001(R) (2020)  - DOI: 10.1103/PhysRevMaterials.4.071001

• Origin of the magnetic spin Hall effect: Spin current vorticity in the Fermi sea 
  A. Mook, R. R. Neumann, A. Johansson, J. Henk, and I. Mertig  
  Phys. Rev. Res. 2, 023065 (2020)  - DOI: 10.1103/PhysRevResearch.2.023065

• Local spin Hall conductivity 
  T. Rauch, F. Töpler, and I. Mertig 
  Phys. Rev. B 101, 264206 (2020)  - DOI: 10.1103/PhysRevB.101.064206

• Elliptical Bloch skyrmion chiral twins in an antiskyrmion system 
  J. Jena, B. Göbel, T. Ma, V. Kumar, R. Saha, I. Mertig, C. Felser, and S. S. P. Parkin
  Nat. Commun. 11: 1115 (2020)  - DOI: 10.1038/s41467-020-14925-6

• Ab initio design of quaternary Heusler compounds for reconfigurable magnetic tunnel diodes and transistors
  T. Aull, E. Şaşıoğlu, I. V. Maznichenko, S. Ostanin, A. Ernst, I. Mertig, and I. Galanakis 
  Phys. Rev. Mater. 3, 124415 (2019)  - DOI: 10.1103/PhysRevMaterials.3.124415

• Spin Seebeck and spin Nernst effects of magnons in noncollinear antiferromagnetic insulators 
  A. Mook, R. R. Neumann, J. Henk, and I. Mertig
  Phys. Rev. B 100, 100401(R) (2019)  - DOI: 10.1103/PhysRevB.100.100401

• Electrical writing, deleting, reading, and moving of magnetic skyrmioniums in a racetrack device
  B. Göbel, A. F. Schäffer, J. Berakdar, I. Mertig, and S. S. P. Parkin
  Sci. Rep. 9, 12119 (2019)  - DOI: 10.1038/s41598-019-48617-z

• Spin and charge currents induced by the spin Hall and anomalous Hall effects upon crossing ferromagnetic/nonmagnetic interfaces
  A. Hönemann, C. Herschbach, D. V. Fedorov, M. Gradhand, and I. Mertig
  Phys. Rev. B 99, 024420 (2019)  - DOI: 10.1103/PhysRevB.99.024420