Later, Morozovska et al., studied the contrast formation mechanism of T-shape boundary between two materials in nanoscale IR spectroscopy . In this model, using two semi-infinite materials with an interface orthogonal to the AFM scanning plane temperature distribution and mechanical displacement of both absorber and the neighboring material is descrcibed, taking into account various factors, including different IR-radiation absorption coefficients, thermo-physical and elastic properties of the two materials. These properties encompass thermal diffusivities, thermal conductivities, and elastic stiffness, as well as thermal expansion coefficients. This model indicates higher modulation frequency would provide a significantly higher spatial resolution.