Marco Battiato
Ultrashort optical laser pulses can generate out-of-equilibrium conditions in solids which can be leveraged to trigger a number of interesting phenomena. One of this is the generation of ultrashort or THz spin current pulses. [1] They are the result of the interplay of transport out-of-equilibrium and the geometry of the multilayer. [1-4]
I will present an historical overview of THz spin currents, [1-4] focusing on how to act on excitation and geometry to control them.
I will also show how THz spin currents can also be induced in semiconductors to achieve record-breaking injection. [5,6].
I will then highlight the fundamental role of such currents in spintronics THz emitters, and how more naïve understanding and simplified descriptions fail to account for important features. [7,8]
I will then showcase new evolutions in the description of out-of-equilibrium transport in realistic materials. [9-15]
References
[1] M. Battiato, K. Carva, P.M. Oppeneer, Phys Rev. Lett. 105, 027203 (2010). [2] D. Rudolf*, C. La-O-Vorakiat*, M. Battiato* R. Adam, J. M. Shaw, E. Turgut, P. Maldonado, S. Mathias, P. Grychtol, H. T. Nembach, T. J. Silva, M. Aeschlimann, H. C. Kapteyn, M. M. Murnane, C. M. Schneider, and P. M. Oppeneer, Nature Comm. 3, 1037 (2012). [3] A. Eschenlohr,* M. Battiato,* P. Maldonado, N. Pontius, T. Kachel, K. Holldack, R. Mitzner, A. Fohlisch, P. M. Oppeneer, and C. Stamm, Nature Mater. 12, 332 (2013). [4] T. Kampfrath, M. Battiato, P. Maldonado, G. Eilers, J. Notzold, S. Mahrlein, V. Zbarsky, F. Freimuth, Y. Mokrousov, S. Blugel, M. Wolf, I. Radu, P. M. Oppeneer, and M. Munzenberg, Nature Nanotechnol. 8, 256 (2013). [5] M. Battiato and K. Held, Phys Rev. Lett. 116, 196601 (2016). [6] L. Cheng, X. Wang, W. Yang, J. Chai, M. Yang, M. Chen, Y. Wu, X. Chen, D. Chi, K. E. J. Goh, J.-X. Zhu, H. Sun, S. Wang, J. C. W. Song, M. Battiato, H. Yang, E. E. M. Chia, Nature Physics (2019). [7] Y Yang, S Dal Forno, M Battiato, Phys Rev B 104 (15), 155437 [8] P Agarwal*, Y Yang*, R Medwal, H Asada, Y Fukuma, M Battiato, R Singh arXiv:2211.15135 [9] M. Wais, K. Held, M. Battiato, Comput. Phys. Commun. 264, 107877 (2021). [10] I. Wadgaonkar, R. Jain, M. Battiato, Comput. Phys. Commun. 263, 107863 (2021). [11] I. Wadgaonkar, M. Wais, M. Battiato, Comput. Phys. Commun. 271, 108207 (2022). [12] F. R. Bagsican, M. Wais, N. Komatsu, W. Gao, L. Weber, K. Serita, H. Murakami, K. Held, F. A. Hegmann, M. Tonouchi, J. Kono, I. Kawayama, M. Battiato, Nano Letters 20, 3098 (2020). [13] M. Wais, F. R. Bagsican, N. Komatsu, W. Gao, K. Serita, H. Murakami, K. Held, I. Kawayama, J. Kono, M. Battiato,M. Tonouchi, under review [14] S. Dal Forno, N. Komatsu, M. Wais, A. Mojibpour, I. Wadgaonkar, S. Ghosh, Y. Yomogida, K. Yanagi, K. Held, J. Kono, M. Battiato, Carbon 186, 465 (2022). [15] O. J Clark, I. Wadgaonkar, F. Freyse, G. Springholz, M. Battiato, J. Sánchez‐Barriga, Advanced Materials (2022)
* Acknowledgement(s): M.B. acknowledges financial support from the Nanyang Technological University, for the grant NAP-SUG, and MOE Singapore for the grants Tier 1 RG75/22, Tier 1 RT13/22, and Tier 2 T2EP50222-0047.