Disorder induced power-law gaps in an insulator-metal Mott transition

Zhenyu Wang, Yoshinori Okada, Jared O'Neal, Wenwen Zhou, Daniel Walkup, Chetan Dhital, Tom Hogan, Patrick Clancy, Young June Kim, Y. F. Hu, Luiz H. Santos, Stephen D. Wilson, Nandini Trivedi, Vidya Madhavan

Research output: Contribution to journalArticlepeer-review


A correlated material in the vicinity of an insulator-metal transition (IMT) exhibits rich phenomenology and a variety of interesting phases. A common avenue to induce IMTs in Mott insulators is doping, which inevitably leads to disorder. While disorder is well known to create electronic inhomogeneity, recent theoretical studies have indicated that it may play an unexpected and much more profound role in controlling the properties of Mott systems. Theory predicts that disorder might play a role in driving a Mott insulator across an IMT, with the emergent metallic state hosting a power-law suppression of the density of states (with exponent close to 1; V-shaped gap) centered at the Fermi energy. Such V-shaped gaps have been observed in Mott systems, but their origins are asyet unknown. To investigate this,we use scanning tunneling microscopy and spectroscopy to study isovalent Ru substitutions in Sr3(Ir1-xRux)2O7 (0 ≤ x ≤ 0.5) which drive the system into an antiferromagnetic, metallic state. Our experiments reveal that many core features of the IMT, such as power-law density of states, pinning of the Fermi energy with increasing disorder, and persistence of antiferromagnetism, can be understood as universal features of a disordered Mott system near an IMT and suggest that V-shaped gaps may be an inevitable consequence of disorder in doped Mott insulators.

Original languageEnglish (US)
Pages (from-to)11198-11202
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number44
StatePublished - Oct 30 2018


  • Correlated electrons
  • Disorder
  • Iridates
  • V-shaped gap

ASJC Scopus subject areas

  • General


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