Superconductor-insulator transitions: Phase diagram and magnetoresistance

Speaker
Igor Burmistrov (Landau Institute for Theoretical Physics, Russia)
Date
19/11/2015 - 15:30 - 14:30Add to Calendar 2015-11-19 14:30:00 2015-11-19 15:30:00 Superconductor-insulator transitions: Phase diagram and magnetoresistance   In this talk I discuss the influence of disorder-induced Anderson localization and of electron-electron interaction on superconductivity in two-dimensional systems. I present the results for the superconducting transition temperature $T_c$, the temperature dependence of the resistivity, the phase diagram, as well as  the magnetoresistance. The analysis is based on the renormalization group for the Finkelstein nonlinear sigma model.  Derived RG equations are valid to the lowest order in disorder but for strong enough electron-electron interaction strength in particle-hole and Cooper channels. The analysis is applied to systems with preserved and broken spin-rotational symmetry as well as with short-range and with long-range (Coulomb) interaction. In the cases of short-range interaction, there is a large parameter region where the superconductivity is enhanced by localization effects.   The RG analysis indicates that the superconductor-insulator transition is controlled by a fixed point with a resistivity $R_c$ of the order of the quantum resistance $R_q = h/ 4e^2$. When a transverse magnetic field is applied, we find a strong nonmonotonous magnetoresistance for temperatures  below $T_c$.    The talk is based on the following papers:   [1] I.S. Burmistrov, I.V. Gornyi, A.D. Mirlin, Phys.Rev. B92, 014506 (2015); Phys. Rev. Lett. 108, 017002 (2012) [2] E.J. Koenig, A. Levchenko, I.V. Protopopov, I.V. Gornyi, I.S. Burmistrov, A.D. Mirlin, arxiv:1509.01474   Resnick Building 209, room 210 Department of Physics physics.dept@mail.biu.ac.il Asia/Jerusalem public
Place
Resnick Building 209, room 210
Abstract
 
In this talk I discuss the influence of disorder-induced Anderson localization and of electron-electron interaction on superconductivity in two-dimensional systems. I present the results for the superconducting transition temperature $T_c$, the temperature dependence of the resistivity, the phase diagram, as well as  the magnetoresistance. The analysis is based on the renormalization group for the Finkelstein nonlinear sigma model. 
Derived RG equations are valid to the lowest order in disorder but for strong enough electron-electron interaction strength in particle-hole and Cooper channels. The analysis is applied to systems with preserved and broken spin-rotational symmetry as well as with short-range and with long-range (Coulomb) interaction. In the cases of short-range interaction, there is a large parameter region where the superconductivity is enhanced by localization effects.  
The RG analysis indicates that the superconductor-insulator transition is controlled by a fixed point with a resistivity $R_c$ of the order of the quantum resistance $R_q = h/ 4e^2$. When a transverse magnetic field is applied, we find a strong nonmonotonous magnetoresistance for temperatures 
below $T_c$. 
 
The talk is based on the following papers:
 
[1] I.S. Burmistrov, I.V. Gornyi, A.D. Mirlin, Phys.Rev. B92, 014506 (2015); Phys. Rev. Lett. 108, 017002 (2012)
[2] E.J. Koenig, A. Levchenko, I.V. Protopopov, I.V. Gornyi, I.S. Burmistrov, A.D. Mirlin, arxiv:1509.01474
 

Last Updated Date : 07/10/2015