Dielectric Constant of Glasses: Evidence for Dipole-Dipole Interactions

F. Ladieu (1, 2) , J. Le Cochec (2, 1) , P. Pari (2) , P. Trouslard (3) , P. Ailloud (2, 1)

1 LPS - Laboratoire Pierre Süe
2 SPEC - UMR3680 - Service de physique de l'état condensé
3 INSTN - Institut National des Sciences et Techniques Nucléaires

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.

Domains: Physics [physics]

F. Ladieu, J. Le Cochec, P. Pari, P. Trouslard, P. Ailloud. Dielectric Constant of Glasses: Evidence for Dipole-Dipole Interactions. Physical Review Letters, 2003, 90 (20), ⟨10.1103/PhysRevLett.90.205501⟩. ⟨cea-01395448⟩