Anisotropic thermopower of the organic superconductor κ-(BEDT-TTF<span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mo>)</mo></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>Cu[N(CN<span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mo>)</mo></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>]Br

R. C. Yu; J. M. Williams; H. H. Wang; J. E. Thompson; A. M. Kini; K. D. Carlson; J. Ren; M.-H. Whangbo; P. M. Chaikin

doi:10.1103/PhysRevB.44.6932

Anisotropic thermopower of the organic superconductor κ-(BEDT-TTF $)_{2}$ Cu[N(CN $)_{2}$ ]Br

R. C. Yu, J. M. Williams, H. H. Wang, J. E. Thompson, A. M. Kini, K. D. Carlson, J. Ren, M.-H. Whangbo, and P. M. Chaikin

Phys. Rev. B 44, 6932 – Published 1 October 1991

Abstract

The thermopower of the organic superconductor κ-(BEDT-TTF $)_{2}$ Cu[N(CN $)_{2}$ ]Br single crystals has been measured in two crystallographic directions a and c within the most conducting organic donor molecule plane. [Here BEDT-TTF represents bis(ethylenethio)-tetrathiafulvalene.] While the thermopower in the a direction is positive, the thermopower in the c direction is negative. The drastic anisotropy in thermopower reveals that the carriers in the a direction are holelike, whereas the carriers in the c direction are electronlike. A calculation based on the tight-binding electronic band structure is able to describe the temperature dependence of the anisotropic thermopower, but with a much reduced band dispersion.