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Title: Nonuniform carrier density in Cd 3 As 2 evidenced by optical spectroscopy

In this paper, we report the detailed optical properties of Cd 3As 2 crystals in a wide parameter space: temperature, magnetic field, carrier concentration, and crystal orientation. We investigate high-quality crystals synthesized by three different techniques. In all the studied samples, independently of how they were prepared and how they were treated before the optical experiments, our data indicate conspicuous fluctuations in the carrier density (up to 30%). These charge puddles have a characteristic scale of 100 μm, they become more pronounced at low temperatures, and possibly, they become enhanced by the presence of crystal twinning. The Drude response is characterized by very small scattering rates (~1 meV) for as-grown samples. Mechanical treatment, such as cutting or polishing, influences the optical properties of single crystals, by increasing the Drude scattering rate and also modifying the high-frequency optical response. Finally, magnetoreflectivity and Kerr rotation are consistent with electronlike charge carriers and a spatially nonuniform carrier density.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5] ;  [1] ;  [6] ;  [6] ;  [7] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [5]
  1. CNRS National Lab. for Intense Magnetic Fields (LNCMI), Grenoble (France)
  2. Swiss Federal Inst. of Technology (EPFL), Ecublens (Switzerland). Inst. of Physics (IPHYS)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Condensed Matter Physics and Materials Science Dept.
  4. Masaryk Univ., Brno (Czech Republic); Central European Inst. of Technology (CEITEC), Brno (Czech Republic)
  5. Univ. of Geneva (Switzerland). Dept. of Quantum Matter Physics (DQMP)
  6. Academy of Sciences of Moldova, Chisinau (Moldova). Inst. of Applied Physics
  7. Princeton Univ., NJ (United States). Dept. of Chemistry
  8. Johns Hopkins Univ., Baltimore, MD (United States). Inst. for Quantum Matter. Dept. of Physics and Astronomy
  9. Johns Hopkins Univ., Baltimore, MD (United States). Inst. for Quantum Matter. Dept. of Physics and Astronomy. Dept. of Chemistry
  10. Johns Hopkins Univ., Baltimore, MD (United States). Inst. for Quantum Matter. Dept. of Physics and Astronomy. Dept. of Chemistry. Dept. of Materials Science and Engineering
  11. CNRS National Lab. for Intense Magnetic Fields (LNCMI), Grenoble (France); Charles Univ., Prague (Czech Republic). Inst. of Physics
Publication Date:
Report Number(s):
BNL-203366-2018-JAAM
Journal ID: ISSN 2469-9950
Grant/Contract Number:
SC0012704; FG02-08ER46544; LQ1601; 692034
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 12; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States); Johns Hopkins Univ., Baltimore, MD (United States); Univ. of Geneva (Switzerland); Swiss Federal Inst. of Technology (EPFL), Ecublens (Switzerland); CNRS National Lab. for Intense Magnetic Fields (LNCMI), Grenoble (France)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); David and Lucile Packard Foundation (United States); Swiss National Science Foundation (SNSF); European Research Council (ERC); French National Research Agency (ANR)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; charge; defects; domains; magneto-optical Kerr effect; optical conductivity; twinning; Dirac semimetal; optical microscopy; optical spectroscopy
OSTI Identifier:
1430846
Alternate Identifier(s):
OSTI ID: 1427882