Magnetotransport (magnetoresistance and anomalous Hall effect) and thermoelectric (Seebeck and anomalous Nernst effect) effects are investigated on epitaxially grown ${\mathrm{Co}}_2\mathrm{Ti}\mathrm{Sn}$ and ${\mathrm{Co}}_2{\mathrm{Ti}}_{0.6}{\mathrm{V}}_{0.4}\mathrm{Sn}$ Heusler thin films. An anomalous Nernst coefficient up to 1.8 $\mu \mathrm{V}/$K is observed in ${\mathrm{Co}}_2{\mathrm{Ti}}_{0.6}{\mathrm{V}}_{0.4}\mathrm{Sn}$ at 220 K, which is almost 12 times larger than in the undoped ${\mathrm{Co}}_2\mathrm{Ti}\mathrm{Sn}$ thin film at 300 K. In analogy to the anomalous Hall angle, we extract the anomalous Nernst angle from experimental results by comparing the anomalous Nernst voltage with the thermopower. The anomalous Nernst angle for ${\mathrm{Co}}_2{\mathrm{Ti}}_{0.6}{\mathrm{V}}_{0.4}\mathrm{Sn}$ is 15% at 220 K, whereas it is only 0.5% for the undoped film. Considering the Mott relation for anomalous Hall and Nernst effects, these experimental results may be accounted for by an enhanced energy derivative of the anomalous Hall conductivity at the Fermi level that is shifted by vanadium doping. These results of a large anomalous Nernst angle provide opportunities to realize spin-caloritronic devices for efficient on-chip energy harvesting based on magnetic Heusler thin films.

The Mott insulator $\kappa -{(\mathrm{BEDT}-\mathrm{TTF})}_2{\mathrm{Ag}}_2{\left(\mathrm{CN}\right)}_3$ 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 quasidegenerate 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 $\kappa -(\text{BEDT}-\text{TTF}){}_2{\mathrm{Cu}}_2\left(\mathrm{CN}\right){}_3$.

$\alpha -(\text{BEDT-TTF}{)}_2{\mathrm{I}}_3$ is a prominent example of charge ordering among organic conductors. In this work, we explore the details of transport within the charge-ordered as well as semimetallic phase at ambient pressure. In the high-temperature semimetallic phase, the mobilities and concentrations of both electrons and holes conspire in such a way to create an almost temperature-independent conductivity as well as a low Hall effect. We explain these phenomena as a consequence of a predominantly interpocket scattering which equalizes mobilities of the two types of charge carriers. At low temperatures, within the insulating charge-ordered phase two channels of conduction can be discerned: a temperature-dependent activation, which follows the mean-field behavior, and a nearest-neighbor-hopping contribution. Together with negative magnetoresistance, the latter relies on the presence of disorder. The charge-ordered phase also features a prominent dielectric peak which bears a similarity to relaxor ferroelectrics. Its dispersion is determined by free-electron screening and pushed by disorder well below the transition temperature. The source of this disorder can be found in the anion layers which randomly perturb BEDT-TTF molecules through hydrogen bonds.

We investigate the dc resistivity and Hall effect of the quasi-two-dimensional organic materials $\kappa –{\left(\mathrm{ET}\right)}_{2}X$, where $X={\mathrm{Ag}}_2{\left(\mathrm{CN}\right)}_3$ and $\text{B}{\left(\mathrm{CN}\right)}_4$ and compare them with the results for $X={\mathrm{Cu}}_2{\left(\mathrm{CN}\right)}_3$. All three compounds are considered to be quantum-spin-disordered Mott insulators. Despite high similarities in chemical composition and crystal structure, large differences in the dc resistivity and Hall coefficient are found. While around room temperature the dc transport properties are dominantly determined by the strength of the electron correlations, upon reducing the temperature, dc transport happens by hopping due to inherent disorder. The most disordered compound with $X={\mathrm{Cu}}_2{\left(\mathrm{CN}\right)}_3$ turns out to have the lowest dc resistivity and the highest charge carrier density, i.e., in the phase diagram it is located closest to the metal-insulator transition. The least disordered compound with $X=\text{B}{\left(\mathrm{CN}\right)}_4$ shows the highest resistivity and the lowest carrier density, i.e., lies farthest from the metal-insulator transition. We explain such counterintuitive behavior within the theory of Mott-Anderson localization as a consequence of disorder-induced localized states within the correlation gap.

The search for new materials for energy-efficient electronic devices has gained unprecedented importance. Among the various classes of magnetic materials driving this search are antiferromagnets, magnetoelectrics, and systems with topological spin excitations. ${\mathrm{Cu}}_3{\mathrm{TeO}}_6$ is a material that belongs to all three of these classes. Combining static electric polarization and magnetic torque measurements with phenomenological simulations we demonstrate that magnetic-field-induced spin reorientation needs to be taken into account to understand the linear magnetoelectric effect in ${\mathrm{Cu}}_3{\mathrm{TeO}}_6$. Our calculations reveal that the magnetic field pushes the system from the nonpolar ground state to the polar magnetic structures. However, nonpolar structures only weakly differing from the obtained polar ones exist due to the weak effect that the field-induced breaking of some symmetries has on the calculated structures. Among those symmetries is the $PT$ (${\overline{1}}^{\prime }$) symmetry, preserved for Dirac points found in ${\mathrm{Cu}}_3{\mathrm{TeO}}_6$. Our findings establish ${\mathrm{Cu}}_3{\mathrm{TeO}}_6$ as a promising playground to study the interplay of spintronics-related phenomena.