Use fn(globe) to control + command + space

karabiner.json

{
  "title": "Use fn(globe) to control + command + space",
  "rules": [
    {
      "description": "Use fn(globe) to control + command + space",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "fn"
          },
          "to": [
            {
              "key_code": "spacebar",
              "modifiers": [
                "left_control",
                "left_command"
              ]
            }
          ]
        }
      ]
    }
  ]
}