Galvanomagnetic phenomena in layered organic conductors (Review)

Abstract

The experimental research on galvanomagnetic phenomena in layered organic conductors at high magnetic fields is discussed in terms of the theoretical ideas about charge transfer phenomena in conductors with a metallic type of conductivity and a quasi-two-dimensional electron energy spectrum of arbitrary form. Attention is devoted mainly to the problem of recovering the dispersion relation of the conduction electrons in layered organic charge-transfer complexes from experimental studies of their magnetoresistance and quantum oscillation phenomena at low temperatures.

Electron transport in multilayer structures in a strong magnetic field

“…It turns out that this condition can be realized in charge transition complexes that possess a multilayered structure. Investigations of galvanomagnetic effects in many layered conductors enable the topological structure of the FS and some details of the electron spectrum to be determined [2]. Analogous information on charge carriers can be obtained by studying the thermoresistance in a strong magnetic field.…”

“…Thus in accessible magnetic fields the small parameter γ exceeds t ⊥ /μ significantly. For this reason the components of the conductivity tensor σ xx , σ yy , σ xy and σ yx are much greater than the rest of the components σ ij , which are proportional to (t ⊥ /μ) 2 .…”

“…where σ (1) ij is the contribution in the conductivity from charge carriers whose states belong to the plane sheet of the FS, and σ (2) ij takes into account the contribution into σ ij made by the rest of the electrons.…”

“…In calculating the electrical conductivity and thermoelectrical coefficients such anisotropy should be taken into account with the help of the low dimensional character of the electron energy spectrum, i.e. the energy of conduction electrons ε(p) depends weakly on the momentum projection p z = np onto the normal n to the layers [1,2]. …”

High-frequency longitudinal oscillations of the quasi-two-dimensional electron liquid

“…Such an anisotropy is typical of cuprates, e.g. YBaCuO in a nonsuperconducting phase, transition metal dichalcogenides (NbSe 2 , TaS 2 ), graphite and its intercalates in particular, as well as a broad family of tetrathiafulvalene salts of (BEDT-TTF) 2 I 3 type [1][2][3][4][5]. A common feature of many layered conductors is their weak electron-energy dependence on the momentum projection p z .…”