Anomalous Sign Change in Hall Coefficient of κ-(BEDT-TTF)2Cu[N(CN)2]Br Under Pressure

Hall effect on the triangular lattice

“…and as n h → 0 we have R 0 H = −1/n h e. The complete density dependence of R 0 H calculated numerically at zero temperature from Eq. ( 9) is displayed in Fig 2 and compared to the limiting cases Eqs (11) and (13). It is clear from this figure that the infinitefrequency R H follows the well-known dependence of the dc Hall coefficient R H (ω = 0) on the carrier charge density.…”

“…Unfortunately we are not aware of any measurements of the ac Hall effect which we could compare to our calculations, although measurements have been done at zero frequency in these materials. 14,15 …”

“…Additionally, many studies have been motivated by the recent discovery of superconductivity in CoO 2 layered compounds ͑cobaltates͒, [8][9][10][11] which are good realizations of an isotropic 2D triangular lattice, 12 and in organic conductors of the bis͑ethylenedithio͒ ͑BEDT͒ family, 13 where one finds various structures resembling the anisotropic triangular system. Several Hall measurements have been undertaken in both organic superconductors 14,15 and cobaltates, especially in the Na x CoO 2 compound. 16,17 In the latter, the anomalous linear increase in the dc Hall coefficient and a recent infrared Hall measurement 16 have motivated recent theoretical works [18][19][20][21] with the aim of investigating the role of correlations in the Hall effect.…”

“…Several Hall measurements have been undertaken in both organic superconductors 10,11 and cobaltates, especially in the Na x CoO 2 compound. In the latter, the anomalous linear increase of the dc Hall coefficient 12 and a recent infrared Hall measurement 12 have motivated further theoretical work on this issue 13,14,15,16 to investigate the effect of correlations in this system and their contribution to the Hall coefficient, but many questions remain open.…”