28 August 2022 to 1 September 2022
Serbian Academy of Sciences and Arts – SASA
Europe/Belgrade timezone

The magnetothermopower of organic superconductor $\rm \kappa-(ET)_2Cu(NCS)_2$: possible charge density wave scenario

S06-CMPSP-109
30 Aug 2022, 14:30
15m
Main Hall (Serbian Academy of Sciences and Arts)

Main Hall

Serbian Academy of Sciences and Arts

Board: S06-CMPSP-109
Oral presentation S06 Condensed Matter Physics and Statistical Physics S06 Condensed Matter Physics and Statistical Physics

Speaker

Danica Krstovska (Ss. Cyril and Methodius University, Faculty of Natural Sciences and Mathematics)

Description

The interlayer magnetothermopower of the organic superconductor $\kappa-\rm (ET)_2Cu(NCS)_2$ is studied at temperatures down to 0.5 K and fields up to 32 T. Analysis of the background magnetothermopower show that at low temperatures it is negative and exhibits an upturn at higher field, producing a dip at a field close to the upper critical field $B_{c2}$. There are clear magnetothermopower quantum oscillations visible above 5 T. The obtained oscillation frequencies are in a good agreement with those previously reported on the magnetoresistance and magnetization quantum oscillations. According to our results, the magnetothermopower in $\kappa-\rm (ET)_2Cu(NCS)_2$ presents features which have already been detected in YBCO and other high-$T_c$ cuprates indicating that some kind of a charge density wave order is also present in the normal state of $\kappa-\rm (ET)_2Cu(NCS)_2$. Most strikingly, our measurements show that there is another dip, again followed by an upturn, in the magnetothermopower of $\kappa-\rm (ET)_2Cu(NCS)_2$ occurring at much higher fields than $B_{c2}$, around the magnetic breakdown field of $\sim 21$ T that is not present in $\rm YBCO$. We propose that the two induced successive phase transitions, consisting of two similarly ordered states each restricted to a finite magnetic field window are in fact charge density wave ordered states arising as a result of the layer-stacking mechanism in the interlayer direction. Our results support and advance some of the previous findings that the superconductivity in the organic superconductor $\kappa-\rm (ET)_2Cu(NCS)_2$ is mediated by a charge density wave order rather than antiferromagnetic fluctuation.

Primary authors

Danica Krstovska (Ss. Cyril and Methodius University, Faculty of Natural Sciences and Mathematics) Dr Eden Steven (Emmerich Research Center, Jakarta Utara, DKI Jakarta 14450, Indonesia) Dr Eun Sang Choi (National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA)

Presentation materials