[Séminaire TQM] Freek Massee (LPS Orsay)

Majorana or not? A closer look at Fe(Se,Te)

The search for Majorana fermions in condensed matter systems has
resulted in a number of putative claims of their discovery. If true,
these exotic particles that are their own anti-particle could be
exploited for error-free quantum computing, turning a fundamental
curiosity into a billion dollar business. Unambiguous proof, however,
is thus far lacking and challenging to provide. A recently proposed
method to distinguish Majorana bound states from more conventional
Andreev-, and Yu-Shiba-Rusinov states is to measure their shot noise
[1]. Using our MHz enabled scanning tunnelling microscope [2], we set
out to investigate three possible Majorana sightings in Fe(Se,Te):
zero energy bound states at single Fe impurities [3] and other native
impurities, linear sub-gap density of states at 1D defects [4] and
vortex cores. In this talk I will discuss our findings.

[1] Phys. Rev. B 104, L121406 (2021)
[2] Rev. Sci. Instrum. 89, 093708 (2018)
[3] Nature Communications 15, 8526 (2024)
[4] Nature Communications 15, 3774 (2024)