{
  "id": "1705.02579",
  "version": "v1",
  "published": "2017-05-07T08:21:15.000Z",
  "updated": "2017-05-07T08:21:15.000Z",
  "title": "Enhancing the spin transfer torque in magnetic tunnel junctions by ac modulation",
  "authors": [
    "Xiaobin Chen",
    "Chenyi Zhou",
    "Zhaohui Zhang",
    "Jingzhe Chen",
    "Xiaohong Zheng",
    "Lei Zhang",
    "Can-Ming Hu",
    "Hong Guo"
  ],
  "comment": "23 pages, 5 figures",
  "journal": "Phys. Rev. B 95, 115417 (2017)",
  "categories": [
    "cond-mat.mes-hall"
  ],
  "abstract": "The phenomenon of spin transfer torque (STT) has attracted a great deal of interests due to its promising prospects in practical spintronic devices. In this paper, we report a theoretical investigation of STT in a noncollinear magnetic tunnel junction under ac modulation based on the nonequilibrium Green's function formalism, and derive a closed-formulation for predicting the time-averaged STT. Using this formulation, the ac STT of a carbon-nanotube-based magnetic tunnel junction is analyzed. Under ac modulation, the low-bias linear (quadratic) dependence of the in-plane (out-of-plane) torque on bias still holds, and the $\\sin\\theta$ dependence on the noncollinear angle is maintained. By photon-assisted tunneling, the bias-induced components of the in-plane and out-of-plane torques can be enhanced significantly, about 12 and 75 times, respectively. Our analysis reveals the condition for achieving optimized STT enhancement and suggests that ac modulation is a very effective way for electrical manipulation of STT.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-05-07T08:21:15.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "spin transfer torque",
      "ac modulation",
      "noncollinear magnetic tunnel junction",
      "nonequilibrium greens function formalism",
      "carbon-nanotube-based magnetic tunnel junction"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. B"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 23,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}