Exotic Properties of Topological Quantum Materials

Student: Krishna Pandey

Degree: Ph.D., December 2021

Major Professor: Dr. Jin Hu

Research Area(s):

Nanoscience & Engineering

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Background/Relevance

  • Moore’s law became challenging below 10nm due to emerging quantum effects.

  • Topological quantum materials with exotic properties are promising for electronic, optoelectronic, and spintronic devices.

Innovation

  • Observe the symmetry-protected electronic states of in Dirac nodal-line semimetal of ZrSiS-family.

  • Tuning the exotic properties of the materials.

Approach

  • Grow single crystals using chemical vapor transport and flux methods.
  • Structural and elemental characterization using x-ray diffraction (XRD) and energy dispersive spectroscopy (EDS).
  • Characterize the electronic properties of the topological Dirac fermions in single crystal.
  • Tune the lattice and composition of the material; characterize the evolution of the Dirac states using resistivity, Hall effect, and quantum oscillation measurements.

Key Results

  • Successful growth of ZrXY ( X=Si, Ge; Y=S, Se Te), RESbTe (RE=La, Ce, Gd, Sm, Pr, Nd) single crystals using chemical vapor transport and flux method.
  • Structural and phase of RESbTe single crystals consistent with atomic radius of RE and previous report of other compounds from same group.
  • Magnetization and Heat capacity measurement shows magnetic nature of NdSbTe and SmSbTe.

Conclusions

  • Single crystals of Dirac nodal-line semimetal are synthesized by chemical vapor transport and flux method.

    SmSbTe, NdSbTe materials  are antiferromagnetic and PrSbTe and LaSbTe does not have magnetic transition till 2K.

Future Work

  • Tune the properties of ZrXY and ReSbte using magnetic field and strain.

    Characterize the evolution of the Dirac states using resistivity, Hall effect, and quantum oscillation measurements.

    Extend area of research to the other materials showing similar properties.