  We report on the unusual behavior of the in-plane thermal conductivity
($\kappa$) and torque ($\tau$) response in the Kitaev-Heisenberg material
$\alpha$-RuCl$_3$. $\kappa$ shows a striking enhancement with linear growth
beyond H = 7 T, where magnetic order disappears, while $\tau$ for both of the
in-plane symmetry directions shows an anomaly at the same field. The
temperature- and field-dependence of $\kappa$ are far more complex than
conventional phonon and magnon contributions, and require us to invoke the
presence of unconventional spin excitations whose properties are characteristic
of a field-induced spin-liquid phase related to the enigmatic physics of the
Kitaev model in an applied magnetic field

Strongly Correlated Electrons