Defected structural modulation in the charge density wave compounds 1T-TaS2 and 1T-TaSe2

The formation of defects in the structural modulation associated with charge density waves (CDW) has been studied by electron microscopy in 1T-TaS 2 and 1T-TaSe 2 . The irradiation with electrons creates lattice defects that pin the phase of the CDW. This pinning induces strain in the CDW and forms the CDW defects. The response of the commensurate CDW in 1T-TaSe 2 is more rigid with respect to the incommensurate 1T-TaS 2 CDW in which the CDW dislocations are much easierly formed Nous avons etudie, par microscopie electronique, la formation de defauts de la modulation structurale associee aux ondes de densite de charge (ODC) dans 1T-TaS 2 et 1T-TaSe 2 . L'irradiation aux electrons cree des defauts ponctuels qui piegent la phase de l'ODC. Ce piegeage augmente la contrainte dans l'ODC et des defauts de l'ODC apparaissent. Dans 1T-TaS 2 les ODC incommensurables sont plus souples que celles commensurables dans 1T-TaSe 2 et des dislocations de l'ODC se creent plus facilement