Temperature dependence of the pressure induced monoclinic distortion in the spin S=1/2S=1/2 Shastry–Sutherland compound SrCu2(BO3)2

• Structure of SrCu2(BO3)2 is studied as a function of pressure and temperature.
• Monoclinic phase appears above 4.0 and below 5.0 Gpa.
• This phase boundary will determine the origin of magnetic order in SrCu2(BO3)2.

We investigate the monoclinic distortion that occurs at 4.7 GPa at room temperature in the frustrated Shastry–Sutherland model quantum magnet SrCu2(BO3)2 as a function of pressure and temperature by means of powder and single crystal angle dispersive synchrotron X-ray diffraction. Our results indicate that the onset of the structural distortion varies in a narrow pressure range between ~4.0 and 5.0 GPa. This result will be useful in order to distinguish between magnetic transitions related to structural changes and potential intrinsic quantum phase transitions that various reports have suggested to take place in SrCu2(BO3)2 at high pressure and low temperature.