AVS 64th International Symposium & Exhibition
    Electronic Materials and Photonics Division Monday Sessions
       Session EM+MI+TF-MoM

Paper EM+MI+TF-MoM2
Towards Topotronics: Combining Chemical Potential Tuning and Strain Engineering to Realize Surface Dominated Transport in Topological Heusler Thin Films

Monday, October 30, 2017, 8:40 am, Room 14

Session: Growth, Electronic, and Magnetic Properties of Heusler Compounds
Presenter: Shouvik Chatterjee, University of California at Santa Barbara
Authors: S. Chatterjee, University of California at Santa Barbara
J.A. Logan, University of California at Santa Barbara
N.S. Wilson, University of California at Santa Barbara
M. Pendharkar, University of California at Santa Barbara
C.J. Palmstrøm, University of California at Santa Barbara
Correspondent: Click to Email

Heusler compounds have emerged as an exciting material system where realization of functional and tunable novel topological phases might be possible[1-4]. PtLuSb is one such compound that has been shown to host topologically non-trivial surface states[5]. However, being a semi-metal without a bulk band gap, exotic transport and thermodynamic properties expected from topological surface states are obscured by contributions from trivial bulk carriers that limits possible device applications[6]. Furthermore, natural defects in the compound leads to unintentional p-type doping resulting in the surface Dirac point lying above the chemical potential[5,6,7].

In this talk, I will present our efforts to address both these issues by a combination of carrier doping and substrate induced bi-axial strain to shift the chemical potential and attempt to open up a bulk gap, respectively. I will show experimental evidence of chemical potential tuning in Au alloyed Pt1-xAuxLuSb thin films where the surface Dirac point can be pushed below the Fermi level. In addition, it is possible to open a bulk-band gap by application of compressive bi-axial strain on thin films synthesized on lattice mismatched substrates. Realization of surface dominated transport in topological Heusler thin films will open up avenues for realization of many exotic phenomena such as quantum anomalous Hall effect[8], axion insulators[9], topological superconductivity[10] and their potential device applications.

References:

  1. S. Chadov et al, Nature Mater, 9, 541 (2010)
  2. H. Lin et al, Nature Mater, 9, 546 (2010)
  3. J. Ruan et al, Nature Commun, 10, 11136 (2016)
  4. C. J. Palmstrøm, Prog. Cryst. Growth Charact. Mater,62, 371-397 (2016)
  5. J. Logan et al, Nature Commun, 7, 11993 (2016)
  6. S. J. Patel et al, Appl. Phys. Lett., 104, 201603 (2014)
  7. Y. G. Yu, X. Zhang and A. Zunger, Phys. Rev. B, 95, 085201 (2017)
  8. C-Z. Chang et al, Science, 340, 167 (2013)
  9. L. Wu et al, Science, 354, 1124 (2016)
  10. L. Fu and C. Kane, Phys. Rev. Lett,100, 096407 (2008)