Physics Commons^™

Charge, Bonding, And Magneto-Elastic Coupling In Nanomaterials, Qi Sun

Doctoral Dissertations

Phonons are exquisitely sensitive to finite length scale effects in a wide variety of materials because they are intimately connected to charge, structure, and magnetism, and a quantitative analysis of their behavior can reveal microscopic aspects of chemical bonding and spin-phonon coupling. To investigate these effects, we measured infrared vibrational properties of bulk and nanoscale MoS₂ [molybdenum disulfide], MnO [manganese(II) oxide], and CoFe₂O₄ [cobalt iron oxide]. From an analysis of frequencies, oscillator strengths, and high-frequency dielectric constants, we extracted Born and local effective charges, and polarizability for MoS₂ and MnO. For MoS₂ nanoparticles, in …