Crystal Growth and Property Tuning of Topological Quantum materials

Student: Krishna Pandey

Degree: Ph.D., December 2022

Major Professor: Dr. Jin Hu

Research Area(s):

Nanoscale Materials & Devices

View Research Quadslide

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), LnSbTe (Ln=La, Ce, Gd, Sm, Pr, Nd) single crystals using chemical vapor transport and flux method.
  • Magnetization, Heat capacity measurement shows the AFM ground state with enhanced electronic correlation in NdSbTe and SmSbTe.
  • Collaborative ARPES study shows the topological Dirac States in 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 LnSbTe 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.