Classical versus critical behavior at the charge-density wave instability in TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane)
Abstract
We present high-precision magnetic-susceptibility data in the vicinity of the 53-K transition in TTF-TCNQ (tetrathiafulvalene-tetracyanoquinodimethane). It is argued that as T-TC-->0, the temperature dependence of the magnetic susceptibility χ mirrors the electronic ordering energy and hence the temperature derivative dχdT behaves like the critical specific heat. A critical-exponent analysis of the susceptibility data yields dχdT~|t|-12≡|(T-TC)TC|-12 in agreement with a classical three-dimensional Ornstein-Zernike approximation for the order-parameter correlations. An anomalous contribution to the magnetic susceptibility in the vicinity of T=48 K was searched for but not found.
- Publication:
-
Physical Review B
- Pub Date:
- December 1977
- DOI:
- 10.1103/PhysRevB.16.5012
- Bibcode:
- 1977PhRvB..16.5012H