Stereoscopic study of angle-dependent interlayer magnetoresistance in the organic conductorκ−(BEDT-TTF)2Cu(NCS)2

Abstract

We stereoscopically studied the angle-dependent interlayer magnetoresistance ${R}_{zz}(\ensuremath{\theta},\ensuremath{\phi})$ of the organic conductor $\ensuremath{\kappa}\text{\ensuremath{-}}{(\text{BEDT-TTF})}_{2}\text{Cu}{(\text{NCS})}_{2}$. A pressure of 7 kbar was applied to render the sample fully metallic. The stereoscopic view enables us to distinguish between quasi-one-dimensional (Q1D) and quasi-two-dimensional (Q2D) types of mixed angular magnetoresistance oscillations. A crossover between Q1D features and Q2D features is observed at $\ensuremath{\phi}\ensuremath{\sim}35\ifmmode^\circ\else\textdegree\fi{}$ when the field rotates in the conducting plane. While the coherence peak in the Q1D region has a constant angular width, $1.4\ifmmode^\circ\else\textdegree\fi{}$, the width of the humplike peak in the Q2D region grows with inverse $\text{cos}\text{ }\ensuremath{\phi}$ dependence up to $25\ifmmode^\circ\else\textdegree\fi{}$. In addition, differences of the $\ensuremath{\phi}$-dependence of ${R}_{zz}^{\ensuremath{\theta}=0}$ and of its temperature dependence support the crossover behavior between Q1D and Q2D dominance.