Layered Organic Conductors in Strong Magnetic Fields

Magnetic quantum oscillations in the charge-density-wave state of the organic metals α-(BEDT-TTF)2MHg(SCN)4 with M = K and Tl

“…The magnetoresistance and magnetization of the α-(BEDT-TTF) 2 MHg(SCN) 4 salts in the CDW state were studied by many authors, see [7] and references therein. The general behavior in a field nearly perpendicular to conducting BEDT-TTF layers is illustrated in Fig.…”

“…This tool has been extensively used not only for exploring conventional metals [1] but also for gaining a deep insight into electronic systems of more complex materials such as cuprate [2,3] and iron-based [4,5] high-temperature superconductors, heavy fermion compounds [6], and organic chargetransfer salts [7]. Particularly the latter class of materials has demonstrated the great potential of the de Haas -van Alphen (dHvA) and Shubnikov -de Haas (SdH) effects in revealing the Fermi surface properties in various electronic states.…”

“…Additionally, the organic compounds, generally characterized by an extraordinary crystal quality, very high anisotropy, and significant electron interactions, offer a vast playground for studying specific features of MQO in layered correlated electron systems, see for a review Refs. [7][8][9][10] and references therein.…”

“…A spectacular example of how MQO and high-field classical magnetoresistance can be used for investigating the electronic state of an organic metal is the work done on α-(BEDT-TTF) 2 MHg(XCN) 4 , where BEDT-TTF stands for the donor organic molecule bis(ethylenedithio)tetrathiafulvalene, M = K, Tl, NH 4 , and Rb, and X = S, Se, see [7] for a review. These are isostructural layered charge-transfer salts with the Fermi surface comprising a pair of slightly warped open sheets (representing a quasi-one-dimensional, q1D, conduction band) and a cylinder (a quasi-two-dimensional, q2D, band) [11,12].…”

“…At temperature T ∼ 10 K three salts, with M = K, Tl, and Rb, and X = S undergo a charge-density-wave (CDW) transition caused by the Peierls-type nesting instability of the open Fermi sheets [7,21]. The compounds remain, however, metallic due to the ungapped cylindrical Fermi surface.…”