​PhD Mid-term Seminar Series: Discovering the versatility of superconducting proximitized platforms: From single molecules to extended nanostructures

CIC nanoGUNE Seminars

Speaker

Katerina Vaxevani
Nanoimaging group, nanoGUNE

When

2023/10/09
11:00

Place

nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian

Host

Nacho Pascual

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Katerina Vaxevani¹,  Dongfei Wang¹, Stefano Trivini¹, Jon Ortuzar¹, Danilo Longo¹, Jose Ignacio Pascual¹,² 

¹CIC nanoGUNE-BRTA, 20018 Donostia-San Sebastian, Spain  

²Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain 

Bridging magnetism and superconductivity has always been a fascinating field where many rich physical phenomena emerge. For example, in the past years, there have been theoretical proposals [1-3], as well as experimental evidence [4] for the realization of Majorana fermions in magnetic chains on superconductors induced by topological end states hosted at their ends. Additionally, the presence of superconducting paring effects in the substrate can protect the excited spin from decaying [5]. In this work, we show that a proximity-induced superconducting gold film can sustain spin excitations of a FeTPP-Cl molecule for more than  80ns. This long value was determined by studying inelastic spin excitations of the S=5/2 multiplet of FeTPP-Cl on Au films over V(100) using scanning tunneling spectroscopy. Moreover, we use a proximitized thin film of silver grown ontop of a bulk niobium crystal as our platform for achieving on-surface synthesis of one-dimensional molecular spin chains that contain the S = 1 triangulene unit as the building block. We report the growth of the silver buffer layer as well as the formation of Ag(111) islands on top of Nb(110). We show the on-surface synthesis route for the triangulene chains, along with the electronic characterization by means of scanning tunneling spectroscopy. Finally, we study the adsorption of a bi-radical molecule on the Ag/Nb proximitized substrate and we compare the results with the deposition on a superconducting bulk crystal, namely Pb(111). 

[1]: P. Brydon, S. D. Sarma, H.-Y. Hui, and J. D. Sau, Physical Review B 91, 064505 (2015). 

[2]: Y. Peng, F. Pientka, L. I. Glazman, and F. Von Oppen, Physical review letters 114, 106801 (2015) 

[3]: S. Nadj-Perge, I. Drozdov, B. A. Bernevig, and A. Yazdani, Physical Review B 88, 020407 (2013) 

[4]: S. Nadj-Perge, I.K. Drozdov, J. Li, H. Chen, S. Jeon, J. Seo, A. H. Macdonald, B. A. Bernevig, and A. Yazdani , Science 346, 602-607 (2014) 

[5]: B. W. Heinrich, L. Braun, J. I. Pascual, and K. J. Franke, Nature Physics 9, 765 (2013).