Acoustic shock wave-induced onset non-distortion-to-distortion type phase transition in siderite (FeCO3) with the absence of spin-state transition: X-ray diffraction and Raman spectroscopic approach

At the beginning of the 21st century, tabletop shock tubes were introduced in dealing with the condensed matter research covering materials of various dimensions ranging from nano to macro such that their structural stabilities have been investigated under extreme-conditions which have flourished in the recent past gaining tremendous amount of interest from material scientists and mineralogist thereby the obtained spectral outcomes in structural transitions aspects have sparked considerable impact. However, to date, a systematic correlation between the acoustic shock-wave impact and static compression experimental results has not been arrived at efficiently. Hence, a lot of experimental results are highly required to gain a better understanding of these two techniques. In the present work, we report the crystallographic structural stability of siderite (FeCO₃) single crystal under acoustic shocked-conditions with a transient shock pressure of 2.0 MPa by ex-situ mode. The impact of shock waves has been examined by X-ray diffraction and Raman spectroscopic techniques. From the analyzed diffraction results, it is observed that the onset of non-distortion-to-distortion type phase-transition has occurred at the 4th shocked condition without any spin transition of Fe²⁺. Raman spectral results also have come up with similar outcomes by the reduction of the peak symmetry of the A_1g Raman band and band splitting of the lattice T-mode. Note that, under static-compression (Zang et al., Geosci. Front. 16 (2025) 101918), the peak symmetry of the A_1g Raman band remains constant up to 16.9 GPa. The singlet of the lattice T-mode remains the same up to 7.1 GPa and it is converted into a doublet band at 10.4 GPa. From the observed results, it is clear that the acoustic shock waves can initiate significant lattice deformations and transitions with a very low transit pressure. Hence, we strongly believe that the acoustic shock wave experiments on minerals can bring out a lot of new implications about the structural stability aspects under static and dynamic loading conditions which will be an open source to comprehend many more new minerals in the upcoming years.