Local off-centering symmetry breaking in the high-temperature regime of SnTe

The local structure of SnTe has been studied using atomic pair distribution function analysis of x-ray and neutron data. Evidence is found for a locally distorted high-temperature state, which emerges on warming from an undistorted rocksalt structure. The structural distortion appears rapidly over a relatively narrow temperature range from 300 to 400 K. A similar effect has been reported in PbTe and PbS and dubbed emphanisis; here we report on emphanisis in a compound that does not contain Pb. The analysis suggests that this effect is unrelated to the low-temperature ferroelectric state in SnTe.