Fig. 4: Heavily damped B2g phonons.
From: Direct observation of excitonic instability in Ta2NiSe5
B2g Raman spectra from 126 K to 546 K. Mode 5 (inverted triangle) exhibits a large blue shift upon cooling, and is heavily damped close to the TC (black solid line). At the highest measured temperature, all three B2g modes are identified: mode 2 (Fig. 3), 5, and 6. Below TC, Ag modes 3 and 4 also become allowed.
