Université Paris-Saclay (Espace Technologique, Bat. Discovery - RD 128 - 2e ét., 91190 Saint-Aubin - France)
Abstract : The 1 kHz real part chi(') of the dielectric constant of a structural glass (a-SiO(2+x)C(1+y)H(z)) was measured at low temperature T. Reducing the sample thickness h below 100 nm weakens the slope /delta(chi('))/delta (T) for T less than or approximately equal 0.1 K, for all measuring fields E. This contrasts with the predictions of the two-level system (TLS) model but is in agreement with the recently proposed delocalization of excitations derived from a field-induced TLS-TLS interaction mechanism. For small h this interaction is screened, which explains the h effects on chi('). Hence, interactions must play a key role in standard thick samples as soon as T less than or approximately equal 0.1 K.
F. Ladieu, J. Le Cochec, P. Pari, P. Trouslard, P. Ailloud. Dielectric Constant of Glasses: Evidence for Dipole-Dipole Interactions. Physical Review Letters, American Physical Society, 2003, 90 (20), ⟨10.1103/PhysRevLett.90.205501⟩. ⟨cea-01395448⟩
