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Séminaire MCBT

Mardi 1er mars à 11h00,
Salle Louis Weil, E424

Orateur : Andrew Fefferman (Ultra-basses températures)
"Elastic measurements of TLSs in amorphous silicon at mK temperatures"

Abstract :

The low temperature properties of glass are distinct from those of crystals due to the presence of poorly understood low-energy excitations. These are usually thought to be atoms tunneling between nearby equilibria, forming tunneling two level systems (TLSs). Elastic measurements on amorphous silicon films suggest that this material contains a variable density of TLSs that decreases as the deposition temperature increases from room temperature to 400 °C [1]. This suggests the possibility of tuning the density of TLSs in a-Si nanomechanical resonators, facilitating measurements of individual TLSs. I will present measurements of the elastic properties of these films down to 10 mK and an analysis in the framework of the standard tunneling model.

[1] X. Liu, D. R. Queen, T. Metcalf, J. Karel and F. Hellman, Phys. Rev. Lett., 113, 025503 (2014)

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