New pressure induced superconductor Sn3S4 using original diamond anvil cell

We have successfully discovered new superconductor Sn3S4 by transport measurements under high pressure using the newly developed original diamond anvil cell (DAC) with electrode and heater made of boron doped diamond thin films. Superconductivity was theoretically predicted and the expected superconducting transition temperatures are varying from 3.3-4.7@10GPa to 31.9K@30GPa depending on the theory [1,2]. The sample Sn3S4 is stable only under high pressure. When the sample placed in the ambient condition, sample was quickly decomposed. Due to this reason, it is necessary to measure the sample without release of the pressure. Then we have developed original diamond cell with 4 electrodes for resistivity measurements and heater electric circuit. Using this DAC, we can heat the sample and measure the resistivity simultaneously. The starting material is mixture of 2SnS and SnS2 and squeezed in DAC up to 30GPa, and heated by electric current through heater circuit. Obtained sample shows superconductivity and Tc gradually increases with decreasing pressure. The maximum Tc is around 13K at 5.6GPa [3]. Below 5.6GPa the sample decomposes and superconductivity also disappears. Our newly developed DAC can simultaneously perform high-pressure synthesis and resistivity measurements, and it is indispensable tool for exploration of pressure induced superconductors such as metal hydride high-Tc materials.