ELFT HÍRADÓ

[Szeminárium koordinátor <sem-admin AT szfki.hu>]

SZFI SeminarÚjfalussy BalázsWigner RCP SZFIZero energy modes of artificial 
spin chains from first principlesTuesday, 31 January 2023, 10:00, KFKI 
Campus, Bldg. 1, 2nd floor, Conference RoomMajorana Zero Modes (MZM) at the 
ends of a chain of magnetic atoms on the surface of a superconductor been of 
high interest over the past few years triggered by their possible 
applications as fault tolerant quantum bits. However, experimentally it is 
still very challenging to uniquely identify MZMs based solely on the spectral 
properties. In such a situation first-principles calculations are especially 
helpful, both in identifying and in designing such topological systems. In 
this talk we present a first-principles computational approach based on a 
microscopic relativistic theory of inhomogeneous superconductivity to 
scrutinize edge states of magnetic chains deposited on the surface of 
superconductors. We investigate in great detail an iron chain on the top of 
Au-covered Nb(110) chain and we make quantitative predictions on various 
properties of the chain based on  quantities well beyond the reach of 
experimental capabilities to uniquely identify the topological phase. We 
confirm that ferromagnetic Fe chains on Au/Nb(110) surface do not support any 
MZM; however, a broad range of spin-spirals can be identified with a robust 
zero energy state displaying signatures of MZMs. For these spirals, we 
explore the structure of various superconducting order parameters and the 
role of spin-orbit coupling. Through additional computational experiments, we 
provide evidence that MZMs are localized to the boundaries of the topological 
region of the chain. The robustness of the MZM states is also demonstrated, 
representing a huge step toward potential experimental realizations. Join 
Zoom 
Meetinghttps://wigner-hu.zoom.us/j/89227994088?pwd=ZktlVWhTSHZBaGlMUDIwbDhHZ3BUQT09Meeting
 ID: 892 2799 4088Passcode: 626366 Minden érdeklődőt szívesen látunk! - 
Everyone is welcome to attend.Attila Nagysem-admin AT szfki.hu