Quantitative Analysis of the Local Phase Transitions Induced by Laser Heating

Functional imaging enabled by scanning probe microscopy (SPM) allows investigations of nanoscale material properties under a wide range of external conditions, including temperature. However, a number of shortcomings preclude the use of the most common material heating techniques, thereby limiting precise temperature measurements. Here we discuss an approach to local laser heating on the micron scale and its applicability for SPM. We applied local heating coupled with piezoresponse force microscopy and confocal Raman spectroscopy for nanoscale investigations of a ferroelectric-paraelectric phase transition in the copper indium thiophosphate layered ferroelectric. Bayesian linear unmixing applied to experimental results allowed extraction of the Raman spectra of different material phases and enabled temperature calibration in the heated region. The obtained results enable a systematic approach for studying temperature-dependent material functionalities in heretofore unavailable temperature regimes.