It has been more than 30 years since the discovery of high-temperature superconductors (HTSCs). The number of articles published on the subject is huge, but the cause of the high superconducting transition temperature T_c is still an open question. The so-called 'pseudogap' HTSC phase — an anomalous 'normal' state — turned out to be as complicated a problem as high-temperature superconductivity itself. Its role remains unexplained. We discuss here only key experimental results with the aim to demonstrate the complexity and intricacy arising in the explanation of problems related to the nature of this unique phenomenon.

Keywords: pseudogap, superconducting gap, tunneling spectroscopy, photoemission, Nernst effect, orders PACS: 74.20.Mn, 74.25.−q, 74.25.Jb, 74.72.−h (all) DOI: 10.3367/UFNe.2020.12.038896 URL: https://ufn.ru/en/articles/2021/9/b/ 000722209600002 2-s2.0-85120799604 2021PhyU...64..890V Citation: Vedeneev S I "Pseudogap problem in high-temperature superconductors" Phys. Usp. 64 890–922 (2021) BibTexBibNote ® (generic)BibNote ® (RIS)MedlineRefWorks Received: 27th, July 2020, revised: 11th, November 2020, accepted: 7th, December 2020 Оригинал: Веденеев С И «Проблема псевдощели в высокотемпературных сверхпроводниках» УФН 191 937–972 (2021); DOI: 10.3367/UFNr.2020.12.038896