# Tomonaga-Luttinger liquid and beyond: the intriguing case of lithium molybdenum purple bronze

**Datum:**5 juli 2016

**Locatie:**University of Antwerp - Campus Groenenborger - Room U.241 - Groeneborgerlaan 171 - 2020 Antwerpen

**Tijdstip:**11 - 12 uur

**Organisatie / co-organisatie:**Condensed Matter Theory

**Korte beschrijving:**CMT seminar presented by Dr. Chudzinski

**Tomonaga-Luttinger liquid and beyond: the intriguing case of lithium molybdenum purple bronze**

We study the low energy physics of a quasi-1D material - lithium molybdenum purple bronze (LMO), Li$_0.9$Mo$_{6}$O$_{17}$, which undergoes a mysterious phase transition at T$^*=28K$ to later become superconductor at 1.9K. Based on band structure results we derive an effective low energy theory within the Tomonaga-Luttinger liquid framework. We estimate the TLL parameters and strength of possible instabilities. Our aim here is to understand these experimental findings that are certainly lying within the 1D regime. In the second part we move beyond the standard 1D theory, we investigate the role of inter-orbital fluctuations. We make a conjecture that the physics around T$^*$ is dominated by multi-orbital excitons. They couple with 1D fermions and properties of such system can be captured using a polaronic picture. Using this model we compute fermionic Green's function to find that the spectral function is broadened with a Gaussian and its temperature dependence acquires an extra T$^1$ factor. Both effects are in perfect agreement with experimental findings. We also compute the resistivity for temperatures above and below the critical temperature T$^*$ which allows us to explain an upturn of the resistivity and interpret the suppression of this extra component when a magnetic field is applied along the conducting axis.

CMT seminar presented by Dr. P.M Chudzinski, University of Utrecht

**Contact e-mail:**lucian.covaci@uantwerpen.be

**Url:**http://cmt.uantwerpen.be