CDW-Exciton Condensate Competition and a Condensate Driven Force

Date
2016
Authors
Özgün, E.
Hakioǧlu, T.
Editor(s)
Advisor
Supervisor
Co-Advisor
Co-Supervisor
Instructor
Source Title
Journal of the Physical Society of Japan
Print ISSN
0031-9015
Electronic ISSN
Publisher
Physical Society of Japan
Volume
85
Issue
8
Pages
1 - 6
Language
English
Journal Title
Journal ISSN
Volume Title
Series
Abstract

We examine the competition between the charge-density wave (CDW) instability and the excitonic condensate (EC) in spatially separated layers of electrons and holes. The CDW and the EC order parameters (OPs), described by two different mechanisms and hence two different transition temperatures TcCDWand TcEC,are self-consistently coupled by a microscopic mean field theory. We discuss the results in our model specifically focusing on the transition-metal dichalcogenides which are considered as the most typical examples of strongly coupled CDW/EC systems with atomic layer separations where the electronic energy scales are large with the critical temperatures in the range TcEC∼ TcCDW∼ 100-200 K. An important consequence of this is that the excitonic energy gap, hence the condensed free energy, vary with the layer separation resulting in a new type of force FEC . We discuss the possibility of this force as the possible driver of the structural lattice deformation observed in some TMDCs with a particular attention on the 1T-TiSe2 below 200 K.

Course
Other identifiers
Book Title
Keywords
Citation
Published Version (Please cite this version)