Emergence of threefold symmetric helical photocurrents in epitaxial low twinned Bi₂Se₃

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{
  "id": "2038", 
  "updated": "2024-01-05T21:33:09.658826+00:00", 
  "metadata": {
    "version": 1, 
    "contributors": [
      {
        "givennames": "Blair", 
        "affiliations": [
          "US Army DEVCOM Army Research Laboratory, Adelphi, MD, 20783"
        ], 
        "email": "blair.c.connelly.civ@army.mil", 
        "familyname": "Connelly"
      }, 
      {
        "givennames": "Patrick", 
        "affiliations": [
          "US Army DEVCOM Army Research Laboratory, Adelphi, MD, 20783"
        ], 
        "familyname": "Taylor"
      }, 
      {
        "givennames": "George", 
        "affiliations": [
          "US Army DEVCOM Army Research Laboratory, Adelphi, MD, 20783"
        ], 
        "email": "george.j.decoster.civ@army.mil", 
        "familyname": "de Coster"
      }
    ], 
    "title": "Emergence of threefold symmetric helical photocurrents in epitaxial low twinned Bi\u2082Se\u2083", 
    "_oai": {
      "id": "oai:materialscloud.org:2038"
    }, 
    "keywords": [
      "topological materials", 
      "electronic structure", 
      "spectroscopy", 
      "terahertz", 
      "photon drag effect", 
      "Experimental"
    ], 
    "publication_date": "Jan 05, 2024, 22:33:09", 
    "_files": [
      {
        "key": "THZ_Data.zip", 
        "description": "Data discussed in paper.", 
        "checksum": "md5:3aaa1f560d3e36dee927b0b70d4aa1e1", 
        "size": 68643
      }
    ], 
    "references": [
      {
        "comment": "(Paper in which the method is described.)", 
        "doi": "https://doi.org/10.48550/arXiv.2303.07808", 
        "citation": "B.C. Connelly et al. arXiv:2303.07808", 
        "url": "https://arxiv.org/abs/2303.07808v2", 
        "type": "Preprint"
      }
    ], 
    "description": "We present evidence of a strong circular photon drag effect (PDE) in topological insulators (TIs) through the observation of threefold rotationally symmetric helicity-dependent topological photocurrents using THz spectroscopy in epitaxially-grown Bi\u2082Se\u2083 with reduced crystallographic twinning. We establish how twinned domains introduce competing nonlinear optical (NLO) responses inherent to the crystal structure that obscure geometry-sensitive optical processes through the introduction of a spurious mirror symmetry. Minimizing the twinning defect reveals strong NLO response currents whose magnitude and direction depend on the alignment of the excitation to the crystal axes and follow the threefold rotational symmetry of the crystal. Notably, photocurrents arising from helical light reverse direction for left/right circular polarizations and maintain a strong azimuthal dependence\u2014a result uniquely attributable to the circular PDE, where the photon momentum acts as an applied in-plane field stationary in the laboratory frame. Our results demonstrate new levels of control over the magnitude and direction of photocurrents in TIs and that the study of single-domain films is crucial to reveal hidden phenomena that couple topological order and crystal symmetries.", 
    "status": "published", 
    "license": "Creative Commons Attribution 4.0 International", 
    "conceptrecid": "2037", 
    "is_last": true, 
    "mcid": "2024.4", 
    "edited_by": 576, 
    "id": "2038", 
    "owner": 1233, 
    "license_addendum": null, 
    "doi": "10.24435/materialscloud:4p-f2"
  }, 
  "revision": 7, 
  "created": "2023-12-29T16:39:33.646778+00:00"
}