Ultra high resolution of 6.2 keV 181Ta in 2H-TaSe2

The 6.2 keV γ-rays of ¹⁸¹Ta have been used to study the hyperfine interaction of ¹⁸¹Ta in the trigonal prismatic charge density wave material 2H-TaSe₂. Using a region of interest drive and an unstrained single crystal sample, we are able to resolve the splitting between the nuclear transition $\text{±}\text{5}\text{2}\text{→ ±}\text{3}\text{2}$ and $\text{±}\text{7}\text{2}\text{→ ±}\text{5}\text{2}$. Our experimental linewidth is that of the Ta metal.