Giant Nernst effect and bipolarity in the quasi-one-dimensional metal Li _0.9Mo ₆O ₁₇

The Nernst coefficient for the quasi-one-dimensional metal, Li _0.9Mo ₆O ₁₇, is found to be among the largest known for metals (ν 500μV/KT at T∼20K), and is enhanced in a broad range of temperature by orders of magnitude over the value expected from Boltzmann theory for carrier diffusion. A comparatively small Seebeck coefficient implies that Li _0.9Mo ₆O ₁₇ is bipolar with large, partial Seebeck coefficients of opposite sign. A very large thermomagnetic figure of merit, ZT∼0.5, is found at high field in the range T?35-50K.