4Hb-TaS2, a naturally occurring van der Waals heterostructure comprised of alternating isolating
1T-TaS2 quantum spin liquid and superconducting 1H-TaS2 layers, shows a plethora of unprece-
dented properties, including magnetic memory effect and time reversal symmetry breaking (TRSB)
in the superconducting state. The evidence for TRSB combined with the observation of π-shifts
in the Little-Parks effect indicates a possibility for chiral superconductivity in 4Hb-TaS2. Here we
performed ultrasound measurements of the high-quality single crystals of 4Hb-TaS2 doped with 1
and 2% of sulfur. We observed two distinct anomalies in the sound velocity and attenuation for
different acoustic modes. The first anomaly is observed at superconducting Tc and the second tran-
sition with onset at T ∗ ∼ 2K. The high sensitivity of the second transition to the applied magnetic
field and sulfur content enabled us to conclude that it is associated with superconductivity. The
strong effect in the attenuation at T ∗ indicates a bulk nature of the transition. We speculated that
T ∗ can be associated with the formation of a two-component superconducting state.