Marvin Schmidt, Savita Priya, Zhijie Huang, Mark Kartsovnik, Natalia Kushch, Martin Dressel
{"title":"Electronic properties of the dimerized organic conductor $κ$-(BETS)$_2$Mn[N(CN)$_2$]$_3$","authors":"Marvin Schmidt, Savita Priya, Zhijie Huang, Mark Kartsovnik, Natalia Kushch, Martin Dressel","doi":"arxiv-2409.08656","DOIUrl":null,"url":null,"abstract":"The two-dimensional molecular conductor $\\kappa$-(BETS)$_2$Mn[N(CN)$_2$]$_3$\nundergoes a sharp metal-to-insulator phase transition at $T_{\\rm MI}\\approx$ 21\nK, which has been under scrutiny for many years. We have performed\ncomprehensive infrared investigations along the three crystallographic\ndirections as a function of temperature down to 10 K, complemented by electron\nspin resonance and dc-transport studies. The in-plane anisotropy of the optical\nconductivity is more pronounced than in any other $\\kappa$-type BEDT-TTF or\nrelated compounds. The metal-insulator transitions affects the molecular\nvibrations due to the coupling to the electronic system; in addition we observe\na clear splitting of the charge-sensitive vibrational modes below $T_{\\rm MI}$\nthat evidences the presence of two distinct BETS dimers in this compound. The\nMn[N(CN)$_2$]$_3^-$ layers are determined by the chain structure of the anions\nresulting in a rather anisotropic behavior and remarkable temperature\ndependence of the vibronic features. At low temperatures the ESR properties are\naffected by the Mn$^{2+}$ ions via $\\pi$-$d$-coupling and antiferromagnetic\nordering within the $\\pi$-spins: The $g$-factor shifts enormously with a\npronounced in-plane anisotropy that flips as the temperature decreases; the\nlines broaden significantly; and the spin susceptibility increases upon cooling\nwith a kink at the phase transition.","PeriodicalId":501171,"journal":{"name":"arXiv - PHYS - Strongly Correlated Electrons","volume":"47 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Strongly Correlated Electrons","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.08656","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The two-dimensional molecular conductor $\kappa$-(BETS)$_2$Mn[N(CN)$_2$]$_3$
undergoes a sharp metal-to-insulator phase transition at $T_{\rm MI}\approx$ 21
K, which has been under scrutiny for many years. We have performed
comprehensive infrared investigations along the three crystallographic
directions as a function of temperature down to 10 K, complemented by electron
spin resonance and dc-transport studies. The in-plane anisotropy of the optical
conductivity is more pronounced than in any other $\kappa$-type BEDT-TTF or
related compounds. The metal-insulator transitions affects the molecular
vibrations due to the coupling to the electronic system; in addition we observe
a clear splitting of the charge-sensitive vibrational modes below $T_{\rm MI}$
that evidences the presence of two distinct BETS dimers in this compound. The
Mn[N(CN)$_2$]$_3^-$ layers are determined by the chain structure of the anions
resulting in a rather anisotropic behavior and remarkable temperature
dependence of the vibronic features. At low temperatures the ESR properties are
affected by the Mn$^{2+}$ ions via $\pi$-$d$-coupling and antiferromagnetic
ordering within the $\pi$-spins: The $g$-factor shifts enormously with a
pronounced in-plane anisotropy that flips as the temperature decreases; the
lines broaden significantly; and the spin susceptibility increases upon cooling
with a kink at the phase transition.