arXiv subjects

M. Pinterić

Publications and source records attributed to M. Pinterić.

5 recordsLinked to original sources

arXiv2026

Electronic structure of Gd-based intermetallics GdCu$_2$Ge$_2$ and GdCuAl$_3$

We present a temperature-dependent reflectivity study of single crystals of the ternary intermetallic compounds GdCu$_2$Ge$_2$ and GdCuAl$_3$ over a broad spectral range (100-18000 cm$^{-1}$, equivalent to 12 meV-2.23 eV) down to 13 K. Below 2000 cm$^{-1}$, the optical spectra are dominated by the response of itinerant charge carriers exhibiting two distinct scattering rates. While the response of the slow charge carriers shows negligible temperature dependence, the more mobile carriers follow the dc resistivity and are significantly suppressed in GdCuAl$_3$, consistent with the higher resistivity of this compound. We attribute this behavior to enhanced electronic correlations arising from the proximity of the Fermi level to van Hove singularities. Supported by density-functional-theory calculations, we further show that elemental substitution can be described as a rigid shift of the Fermi level, i.e., doping, whereas changes in the crystalline symmetry have only minor effects on the electronic structure.

cond-mat.str-el↗

arXiv2017

Importance of van der Waals interactions and cation-anion coupling in an organic quantum spin liquid

The Mott insulator $β'$-EtMe$_3$Sb[Pd(dmit)$_2$]$_2$ belongs to a class of charge transfer solids with highly-frustrated triangular lattice of $S=1/2$ molecular dimers and a quantum-spin-liquid ground state. Our experimental and ab initio theoretical studies show the fingerprints of strong correlations and disorder, important role of cation-dimer bonding in charge redistribution, no sign of intra- and inter-dimer dipoles, and the decisive van der Waals contribution to inter-dimer interactions and the ground state structure. The latter consists of quasi-degenerate electronic states related to the different configurations of cation moieties which permit two different equally probable orientations. Upon reducing the temperature, the low-energy excitations slow down, indicating glassy signatures as the cation motion freezes out.

cond-mat.str-el↗

arXiv2016

Anions effects on the electronic structure and electrodynamic properties of the Mott insulator $κ$-(BEDT-TTF)$_2$Ag$_2$(CN)$_{3}$

The Mott insulator $κ$-(BEDT-TTF)$_2$Ag$_2$(CN)$_3$ forms a highly-frustrated triangular lattice of $S=1/2$ dimers with a possible quantum-spin-liquid state. Our experimental and numerical studies reveal the emergence of a slight charge imbalance between crystallographically inequivalent sites, relaxor dielectric response and hopping dc transport. In a broader perspective we conclude that the universal properties of strongly-correlated charge-transfer salts with spin liquid state are an anion-supported valence band and cyanide-induced quasi-degenerate electronic configurations in the relaxed state. The generic low-energy excitations are caused by charged domain walls rather than by fluctuating electric dipoles. They give rise to glassy dynamics characteristic of dimerized Mott insulators, including the sibling compound $κ$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$.

cond-mat.str-el↗

arXiv2014

Low-Energy Excitations in the Quantum Spin-Liquid $κ$-(BEDT-TTF)$_2$Cu$_2$(CN)$_{3}$

The electrodynamic response of the organic spin-liquid candidate $κ$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$ has been measured in an extremely wide energy range ($10^{-13}$ to 2 eV) as a function of temperature (5 to 300 K). Below the Mott gap, excitations from the un-gapped spinon continuum cause a considerable contribution to the infrared conductivity, as suggested by the U(1) gauge theory. At THz frequencies we can identify a power-law behavior $σ(ω) \propto ω^β$ with two distinct exponents $β$ that change from 0.9 to 1.3 at low temperatures. The corresponding crossover scales with temperature: $\hbarω_c \approx k_B T$. The observed exponents differ by more than a factor of 2 from the theoretically predicted ones. The findings are compared with those obtained on Herbertsmithites.

cond-mat.str-el↗

arXiv2012

Cooperative dynamics in charge-ordered state of alpha-(BEDT-TTF)2I3

Electric-field-dependent pulse measurements are reported in the charge-ordered state of alpha-(BEDT-TTF)2I3. At low electric fields up to about 50 V/cm only negligible deviations from Ohmic behavior can be identified with no threshold field. At larger electric fields and up to about 100 V/cm a reproducible negative differential resistance is observed with a significant change in shape of the measured resistivity in time. These changes critically depend whether constant voltage or constant current is applied to the single crystal. At high enough electric fields the resistance displays a dramatic drop down to metallic values and relaxes subsequently in a single-exponential manner to its low-field steady-state value. We argue that such an electric-field induced negative differential resistance and switching to transient states are fingerprints of cooperative domain-wall dynamics inherent to two-dimensional bond-charge density wave with ferroelectric-like nature.

cond-mat.str-el↗