[Landau ITP Seminars] Thursday 22.10.2026 - ITP/CAS Colloquium

[sapostolov]

Уважаемые коллеги!

На онлайн коллоквиуме по теоретической физике в четверг 22.10 будут 
заслушаны 2 доклада:

1) 10:00 по московскому времени:
Pavel Grigoriev (L. D. Landau Institute for Theoretical Physics, RAS)
Interplay of Superconductivity and Charge/Spin Density Wave with 
Imperfect Nesting

The interplay between superconductivity (SC) and charge or spin density 
wave (DW) appears in various strongly-correlated electron systems, 
including most high-Tc superconductors. Often these two phenomena 
coexist. The spatially uniform DW-SC coexistence may appear in the case 
of imperfect nesting of Fermi-surface (FS). Then the DW opens a gap in 
electron spectrum only on some FS parts. One could expect the 
exponential decrease of superconducting transition temperature Tc on DW 
background because of it exponential dependence on electron density of 
states (DoS) at the Fermi level according to BCS theory. However, 
usually, one observes a more complicated SC-DW interplay: the 
superconducting transition temperature Tc has a dome-like shape, being 
the highest at the quantum critical point (QCP) where the DW is 
suppressed by an external parameter. Tc of SC is often higher on the DW 
background than without DW. Why the enhancement of SC coupling by 
critical DW fluctuations overcomes the DoS reduction by DW? 
Surprisingly, the DoS at the Fermi level withstands the DW with 
imperfect nesting because the dispersion of remaining electrons on the 
Fermi surface is strongly renormalized. This explains the observed 
increase of SC transition temperature in DW state.

Biography

Prof. Pavel Grigoriev, obtained his Ph.D. (2001) and Doctor of Science 
(2015) degrees from the Landau Institute for Theoretical Physics. After 
the postdoctoral research under supervision of Lev Gor'kov at NHMFL 
(Tallahassee, USA) is a permanent researcher at Landau Institute. Since 
2015 also a professor at National University of Science and Technology 
MISIS. His research interests include strongly correlated electron 
systems, magnetoresistance of layered conductors, neutron physics, 
liquid helium.

2) 11:00:00 по московскому времени:
Xianxin Wu (Institute of Theoretical Physics, CAS)
Microscopic Mechanisms of Exotic Electronic Orders and Unconventional 
Superconductivity

Uncovering the microscopic mechanisms of unconventional electronic 
orders and high-Tc superconductivity remains a central challenge in 
correlated-electron physics. In this talk, I will discuss two examples 
of how electronic structure and interactions can generate exotic quantum 
phases. First, I will present a theoretical scenario where a sublattice 
interference effect associated with van Hove singularities drive the 
long-sought loop-current order in kagome lattices, and discuss exotic 
pairing states in kagome metals. I will then introduce an itinerant 
framework in which scattering between states of opposite mirror parity 
unifies the understanding of magnetism and unconventional 
superconductivity in high-Tc multilayer nickelates.

Biography

Dr. Xianxin Wu received his Ph.D. from the Institute of Physics, Chinese 
Academy of Sciences, in 2016. From 2016 to 2022, he conducted 
postdoctoral research at the University of Würzburg and the Max Planck 
Institute for Solid State Research. In 2022, he joined the Institute of 
Theoretical Physics, Chinese Academy of Sciences. His research focuses 
on high-Tc superconductivity, topological superconductivity, strongly 
correlated electron systems, and topological phases of matter.

Zoom: 391 106 6816
Passcode: 202512

https://us06web.zoom.us/j/3911066816?pwd=Lay3r6eik0aNphsA8PEatwW12kCzno.1
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