Pressure-induced superconductivity and phase transition in PbSe and PbTe

Abstract The IV–VI semiconducting chalcogenides are a large material family with distinct physical behavior. Here, we systematically investigate the effect of pressure on the electronic and crystal structures of PbSe and PbTe by combining high-pressure electrical transport and synchrotron x-ray diffraction (XRD) measurements. The resistivity of PbSe and PbTe changes dramatically under high pressure and a non-monotonic evolution of ρ ( T ) is observed. Both PbSe and PbTe are found to undergo semiconductor–metal transition upon compression and show superconductivity under higher pressure. The structural evolutions from the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>F</mml:mi> <mml:mi>m</mml:mi> <mml:mover accent="true"> <mml:mn>3</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mi>m</mml:mi> </mml:mrow> </mml:math> to Pnma phase and then to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>P</mml:mi> <mml:mi>m</mml:mi> <mml:mover accent="true"> <mml:mn>3</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mi>m</mml:mi> </mml:mrow> </mml:math> phase in PbSe are verified by the x-ray diffraction. The present findings reveal the internal correlation between the structural evolution and the physical properties in lead chalcogenides.