{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"4068e92f9d60ba04c4d78c3d6258b995fd3d5bb68debd9d94de9163cafab5b0a","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["8ac846627c2531abab270c19b179913f07293e9511564d65c36ace4ce73d4cdf","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"c0993e26e3137c0ef269666b500c35b81c7a305ca55bf397097372e50c0f6a0d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":["ai:gpt-5.5"],"external_id":"cm.one-over-f-noise.hooge-parameter","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"The strength of 1/f noise per charge carrier, measured by a number called the Hooge parameter, differs by many orders of magnitude between materials and samples. No theory predicts it from a material's structure and defect content.","posed_since":"1969","precise":"In $S_R(f)/R^{2} = \\alpha_H/(N_c f)$, measured $\\alpha_H$ spans more than four orders of magnitude between high-quality crystals and disordered films, around the originally proposed universal value $2 \\times 10^{-3}$. For one material class (for example metal films or doped Si), determine how $\\alpha_H$ depends on the density and type of mobile defects, whether the noise arises from mobility or carrier-number fluctuations, and derive $\\alpha_H$ from a microscopic fluctuator model with independently measured defect parameters.","problem_ref":"8ac846627c2531abab270c19b179913f07293e9511564d65c36ace4ce73d4cdf","references":"","settled_by":"$\\alpha_{\\mathrm{H}}$ measured on a sample series with controlled, independently quantified defect density, reproduced by a fluctuator model without free parameters.","status_note":"","title":"What sets the magnitude of the Hooge noise parameter?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"47a7c6ec5f6db74c09b327aefbab99c11f8302f770fe0733381a47781f251d64","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"09d364d7f65bf57a7df5a9d7de08d99098e8894968be5e0841fd406eca0272c6","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"6C6bXBzXcGVz6LvxIfr9n7oFZvo_0AikUNe4A6TWeGLLZ--ATMeud8l-OzeLnF8fSInWBkAMpLcE9O8TMNO1Aw"},"schema":"pubphys.envelope/1"},"record_hash":"47a7c6ec5f6db74c09b327aefbab99c11f8302f770fe0733381a47781f251d64","leaf_index":2986}