1 research outputs found
Impact of Pressure on the Resonant Bonding in Chalcogenides
Resonant
bonding has been appreciated as an important feature in some chalcogenides.
The establishment of resonant bonding can significantly delocalize
the electrons and shrink the band gap, leading to low electrical resistivity
and soft optical phonons. Many materials that exhibit this bonding
mechanism have applications in phase-change memory and thermoelectric
devices. Resonant bonding can be tuned by various means, including
thermal excitations and changes in composition. In this work, we manipulate
it by applying large hydrostatic-like pressure. Synchrotron X-ray
diffraction and density functional theory reveal that the orthorhombic
lattice of GeSe appears to become more symmetric and the Born effective
charge has significantly increased at high pressure, indicating that
resonant bonding has been established in this material. In contrast,
the resonant bonding is partially weakened in PbSe at high pressure
due to the discontinuity of chemical bonds along a certain lattice
direction. By controlling resonant bonding in chalcogenides, we are
able to modify the material properties and tailor them for various
applications in extreme conditions