News

Electrically controlled spin current

Researchers of our Institute have created electrically controlled spin currents in a graphene-based nanostructure. Published in Nano Letters, in collaboration with Chalmers.

 

Zoltán Kovács-Krausz, Anamul Md Hoque, Péter Makk, Bálint Szentpéteri, Mátyás Kocsis, Bálint Fülöp, Michael Vasilievich Yakushev, Tatyana Vladimirovna Kuznetsova, Oleg Evgenevich Tereshchenko, Konstantin Aleksandrovich Kokh, István Endre Lukács, Takashi Taniguchi, Kenji Watanabe, Saroj Prasad Dash, and Szabolcs Csonka
Electrically Controlled Spin Injection from Giant Rashba Spin–Orbit Conductor BiTeBr
Nano Letters 20, 4782 (2020)
 
Home page of the BME Nanoelectronics research group: http://nanoelectronics.physics.bme.hu/

Material for future devices

Material for future batteries and spintronic devices
 
Lithium shortage is an arising challenge due to the ever-increasing demand for lithium-ion based batteries. The problem could be solved by replacing lithium with sodium, which is a lot more abundant on Earth. However, until now, no one has managed to dope graphite -- which is the most common electrode in batteries -- with sodium in large enough concentrations. The researchers of the Spin-spectroscopy group of the Institute of Physics report the successful synthesis of highly sodium-doped graphene. The result was achieved in an international collaboration, and published by ACS Nano:
 
B. G. Márkus, P. Szirmai, K. F. Edelthalhammer, P. Eckerlein, A. Hirsch, F. Hauke, N. M. Nemes, Julio C. Chacón-Torres, B. Náfrádi, L. Forró, T. Pichler, and F. Simon
Ultralong Spin Lifetime in Light Alkali Atom Doped Graphene
 
The spin lifetime of electrons is also very long in this material, thus making it a good candidate for future spintronic devices. The publication was also highlighted by news site of the collaborating partner, the Swiss Federal Institute of Technology in Lausanne (EPFL). EPFL has a long-standing and fruitful collaboration with BME, and according to the latest QS World University Rankings, is the world's 14th best university.
 
Graphene with sodium could make better batteries
https://actu.epfl.ch/news/graphene-with-sodium-could-make-better-batteries/
 
Web page of the research group: http://dept.physics.bme.hu/SpinSpectroscopy

 

Publication prizes

Two of the publication prizes of BME and the Pro Progressio Foundation were awarded to papers authored by our colleauges in the Institute of Physics, published in Nature Communications and Nature materials.

 

Prize: Most significant scientific publication of BME in 2019

 

Balázs Dóra, Markus Heyl, Roderich Moessner 
The Kibble-Zurek mechanism at exceptional points
Nature Communications 10, 2254 (2019)
https://doi.org/10.1038/s41467-019-10048-9

 

BME author: Balázs Dóra, professor, Department of Theoretical Physics

 

 

Prize: Most excellent scientific publication of BME in 2015-2019

 

I. Kézsmárki, S. Bordács, P. Milde, E. Neuber, L. M. Eng, J. S. White, H. M. Rønnow, C. D. Dewhurst, M. Mochizuki, K. Yanai, H. Nakamura, D. Ehlers, V. Tsurkan & A. Loidl 
Néel-type skyrmion lattice with confined orientation in the polar magnetic semiconductor GaV4S8
Nature Materials 14, 1116 (2015)
 
BME authors: István Kézsmárki, professor, and Sándor Bordács, associate professor, Department of Physics
 
 

 

Via: http://proprogressio.hu/muegyetemi-publikacios-teljesitmenyeket-elismero-dij/

BME Best Teacher Award for Péter Vankó

Péter Vankó, associate professor of the Department of Physics, receives the Best Teacher Award of BME in 2019 Fall semester. Interview (in Hungarian) in the student's magazine Műhely.

 

,,Szakmai biztonság, felszabadultság, emberség''
interview (in Hungarian) with Péter Vankó
Műhely, XVIII. évfolyam, 6. szám, 2020. április 20.
http://ehk.bme.hu/muhely/20200420/megjelent-a-nbsp-xviii-evf-6-lapszam
 

The Yu-Shiba-Rusinov state

BME physicists find an unexpectedly large extension of the Yu-Shiba-Rusinov (YSR) state in a superconducting nanostructure, a result which paves the way toward topologically protected qubits. The work is published in Nature Communications, in collaboration with colleagues University of Basel.

 

Recent years have bought new quantum bit proposals, which are based on low-energy bound states in superconducting environment. These qubits would combine the properties of spin-based and superconductor-based qubits, and they are robust against noise-induced information loss. One such qubit is based on the so-called Yu-Shiba-Rusinov (YSR) state: a linear chain, engineered from such bound states, could host noise-protected quantum states. Due to the very small spatial extension of these states, making two of them interact with one another is difficult. Up to now, this was only possible by a very delicate technique, where individual ferromagnetic atoms are deposited next to each other.

 

In their new study, the MTA-BME Momentum Nanoelectronics Research Group realizated the YSR state in an alternative way: they attached an artificial atom to the superconductor's surface. This is the first time that the spatial extension of such a YSR state is measured. The measurement brought a surprising result: The size of the YSR state reaches 50-200 nanometers, which is significantly larger than the spatial extension observed in the case of real, ferromagnetic atoms. With state-of-the-art nanotechnology, artificial atoms can be routinely fabricated at such distances, which paves the way to realize YSR chains. The large extension of the YSR state has been theoretically explained in collaboration with another research group of BME’s Institute of Physics, the BME-MTA Exotic Quantum Phases Momentum Group.

 

Figure: Measurement of the spatial extension of the Yu-Shiba-Rusinov state. As an artificial atom (quantum dot, QD) is attached to a superconductor (SC), a Yu-Shiba-Rusinov state (blue) forms at the quantum dot and its surrounding in the superconductor. The YSR state is probed by measuring the current (IT) through an electrode on the left side of the superconductor. Despite the relatively large, 200 nanometer width of the superconductor, the YSR state was observed by the tunnel probe. In agreement with our calculations, the size of the YSR state increases further in a finite external magnetc field.

 
Zoltán Scherübl, Gergő Fülöp, Cătălin Paşcu Moca, Jörg Gramich, Andreas Baumgartner, Péter Makk, Tosson Elalaily, Christian Schönenberger, Jesper Nygård, Gergely Zaránd, Szabolcs Csonka
Large spatial extension of the zero-energy Yu-Shiba-Rusinov state in magnetic field
Nature Communications 11, 1834 (2020).
https://www.nature.com/articles/s41467-020-15322-9
https://arxiv.org/abs/1906.08531.

PIN code of atomic synapses revealed

Single-atom-sized wires carry the electric current in the memristors created by our colleagues in the Nanoelectronics research group. Research published in Nano Letters.

 

Tímea Nóra Török, Miklós Csontos, Péter Makk, András Halbritter
Breaking the Quantum PIN Code of Atomic Synapses
Nano Lett. 20, 1192 (2020)
https://doi.org/10.1021/acs.nanolett.9b04617

 

 

Website of the research group: http://nanoelectronics.physics.bme.hu/

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