Veranstaltungsarchiv 2016

Hier finden Sie vergangene Veranstaltungen des MPSDs und der MPSD-Forschungsgruppen an der Universität Hamburg.

MPSD Seminar

5737 1465391379

Collective modes of the electron-hole condensate in the (putative) excitonic insulator 1T-TiSe₂

TiSe₂ is one of the simplest charge density wave (CDW) materials, forming a 2×2 superlattice below a transition temperature T_C = 200 K, but the origin of this phase is controversial. Its nearly inverted band structure led early authors to identify TiSe₂ as an “excitonic insulator,” which is an electronic instability involving spontaneous proliferation of excitons. The problem is that the CDW also exhibits a sizeable lattice distortion, leading later authors to identify it as a conventional Peierls phase. That said, an excitonic phase would also create an incidental lattice distortion, since the interaction with phonons can’t be switched off. The arguments on the matter have gone in circles for decades. [mehr]

 
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