First Order Phase Transition in IrTe2 Studied by Optical Second Harmonic Generation

ORAL

Abstract

Optical second harmonic generation (SHG) is a powerful and versatile technique used to study the electronic symmetry of surfaces and interfaces. Transition metal compounds, such as IrTe2, are ideal candidates for broken symmetry studies. X-ray diffraction measurements of IrTe2 reveal that when cooling below Tc,bulk ~ 280 K a first order structural bulk phase transition from 1x1x1 (at high temperatures) to 5x1x5 (at low temperatures) occurs. On the surface electron diffraction shows 1x1 to 5x1 phase change at Tc,surface ~ 270 K. To understand the nature of this transition, SHG coupled with azimuthal sample rotation is used to probe the phase change across Tc,surface. We observe the hysteresis loop of SHG intensity with a ΔT of ~ 3K, in agreement with the previous electron diffraction measurement. Four polarization combinations are utilized allowing sensitivity to both the in-plane (Te-Te bonds) and out-of-plane (Ir-Te bonds) surface responses. In addition, rotational anisotropy SHG measurements above and below Tc,surface yield distinct surface symmetry patterns. Comparing the results of SHG to bulk properties, key insight into the nature of the phase transition is obtained.

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Presenters

  • Joel Taylor

    Department of Physics and Astronomy, Louisiana State University

Authors

  • Joel Taylor

    Department of Physics and Astronomy, Louisiana State University

  • Zhenyu Zhang

    Department of Physics and Astronomy, Louisiana State University

  • Guixin Cao

    Department of Physics and Astronomy, Louisiana State University

  • Rongying Jin

    Department of Physics and Astronomy, Louisiana State University, Physics and Astronomy, Louisiana State Univ - Baton Rouge, Department of Physcis and Astronomy, Louisiana State University, Department of Physics & astronomy, Louisiana state University, Department of Physics, Louisiana State University, Louisiana State Univ - Baton Rouge, Physics and Astronomy, Louisiana State University, Physics, Louisiana State Univ, Department of Physics and Astronomy,, Louisiana State Univ - Baton Rouge

  • Louis Haber

    Department of Chemistry, Louisiana State University

  • E Plummer

    Physics and Astronomy, Louisiana State Univ - Baton Rouge, Department of Physcis and Astronomy, Louisiana State University, Louisiana State Univ - Baton Rouge, Department of Physics, Louisiana State University, Dept. of Physics and Astronomy , Louisiana State University, USA, Department of Physics & Astronomy, Louisiana State University, Department of Physics and Astronomy, Louisiana State University