6533b835fe1ef96bd129f5e8

RESEARCH PRODUCT

HIERARCHICAL MELTING OF ONE-DIMENSIONAL INCOMMENSURATE STRUCTURES

Rolf Schilling

subject

RenormalizationPhysicsCondensed matter physicsHierarchy (mathematics)ThermalOrders of magnitude (speed)Sensitivity (control systems)Type (model theory)Continued fractionStructure factor

description

We study the low—temperature properties of quasi one—dimensional, incommensurate structures which are described by a Frenkel—Kontorova—like model. A new type of renormalization method will be presented, which is determined by the continued fraction expansion of the incommensurability ratio ζ. (This method yields a hierarchy of renormalized Hamiltonians ϰ(n,p) describing the thermal behavior for temperatures T = O(T(n,p)), where T(n,p) follows from the continued fraction expansion of ζ. By means of this method the low—temperature specific heat c(T) and the static structure factor S(q) are calculated for fixed ζ. c(T) possesses a hierarchy of Schottky anomalies related to the rational approximates of ζ and S(q) exhibits more and more satellites when the temperature is decreased. Our theoretical approach predicts a high sensitivity on a small change of ζ. For instance c(T) and S(q) may change by several orders of magnitude if ζ is changed by, e.g one per cent only. Finally our results are compared with experimental data.

https://ora.ox.ac.uk/objects/uuid:1efb4e77-e321-44d1-b3cb-d10685673f31