  Two dimensional semiconducting transition metal dichalcogenides (TMDs)
exhibit an intrinsic Ising spin orbit coupling (SOC) along with a valley
contrasting Berry curvature, which can generate a purely anomalous spin and
valley Nernst signal driven by a thermal gradient. We show that a small
Bychkov-Rashba coupling, which is present in gated TMDs, can enhance the valley
Nernst signal by at least 1-2 orders of magnitude. We find that the Nernst
signal in these materials is dominated by the anomalous geometrical
contribution, and the conventional contribution is much weaker. Importantly,
the Nernst signal is also highly tunable by external gating. Although the total
Nernst signal vanishes due to time reversal (TR) symmetry, a small magnetic
coupling lifts the valley degeneracy and generates an amplified Nernst
response. Additionally, we also discuss the Nernst response of bilayer TMDs,
and show a similar enhancement and modulation of the Nernst signal due to
Rashba SOC. Our predictions are highly pertinent to ongoing experimental
studies in TMDs. The generated large anomalous Nernst signal can directly probe
the presence of a large Berry curvature in these materials, and may serve as a
promising tunable platform for caloritronics applications.
