CDW-Exciton Condensate Competition and a Condensate Driven Force
| Autor: | Ege Özgün, T. Hakioğlu |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Physics
Condensed matter physics Band gap Computer Science::Information Retrieval Exciton General Physics and Astronomy Order (ring theory) Computer Science::Computation and Language (Computational Linguistics and Natural Language and Speech Processing) 02 engineering and technology Electron Type (model theory) 021001 nanoscience & nanotechnology 01 natural sciences Condensed Matter - Strongly Correlated Electrons Mean field theory 0103 physical sciences 010306 general physics 0210 nano-technology Electronic energy Energy (signal processing) |
| Zdroj: | Journal of the Physical Society of Japan |
| Popis: | 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 $T^{CDW}_c$ and $T^{EC}_c$, 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 $T^{EC}_c \sim T^{CDW}_c \sim 100-200 K$. 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 ${\cal F}_{EC}$. 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 $ 1 {\it T}$-$TiSe_2$ below $200 K$. Comment: 8 pages, 5 figures |
| Databáze: | OpenAIRE |
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