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The quasi-one-dimensional organic conductors (TMTTF)$_2X$ with non-centrosymmetric anions commonly undergo charge- and anion-order transitions upon cooling. While for compounds with tetrahedral anions ($X$ = BF$_4^-$, ReO$_4^-$, and ClO$_4^-$) the charge-ordered phase is rather well understood, the situation is less clear in the case of planar triangular anions, such as (TMTTF)$_2$NO$_3$. Here we explore the electronic and structural transitions by transport experiments, optical and magnetic spectroscopy. This way we analyze the temperature dependence of the charge imbalance 2$delta$ and an activated behavior of $rho(T)$ with $Delta_{rm CO}approx 530$~K below $T_{rm CO} = 250$~K. Since (TMTTF)$_2$NO$_3$ follows the universal relation between charge imbalance 2$delta$ and size of the gap $Delta_{rm CO}$, our findings suggest that charge order is determined by TMTTF stacks with little influence of the anions. Clear signatures of anion ordering are detected at $T_{rm AO}=50$~K. The tetramerization affects the dc transport, the vibrational features of donors and acceptors, and leads to formation of spin singlets.
The electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ is studied by angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant discrepancies to band theory. We demonstrate that the measur
We have measured the high field magnetoresistence and magnetization of quasi-one- dimensional (Q1D) organic conductor (Per)2Pt(mnt)2 (where Per = perylene and mnt = maleonitriledithiolate), which has a charge density wave (CDW) ground state at zero m
An inductive method is used to follow the magnetic field-dependent susceptibility of the coupled charge density wave (CDW) and spin-Peierls (SP) ordered state behavior in the dual chain organic conductor Perylene$_2$[Pt(mnt)$_2$]. In addition to the
We study the electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ by means of density-functional band theory, Hubbard model calculations, and angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal s
Magnetic properties in the quasi-one-dimensional organic salt (TMTTF)2SbF6 are investigated by 13C NMR under pressures. Antiferromagnetic phase transition at ambient pressure (AFI) is confirmed. Charge-ordering is suppressed by pressure and is not ob