The University of Tennessee, Knoxville

Joint Institute for Advanced Materials


Condensed Matter Seminars

2017

The seminars are held every Friday in the seminar room of the Joint Institute for Advanced Materials (Room 147).

Date Speaker Title
December 8 Dr. Shang-Shun Zhang (University of Tennessee) Paring from strong repulsion in triangular lattice Hubbard model

Abstracts

December 8

Dr. Shang-Shun Zhang (University of Tennessee)

Paring from strong repulsion in triangular lattice Hubbard model

The generation of an effective attraction between electrons out of the bare Coulomb repulsion is a long sought-after goal of the condensed matter community. In this talk I will describe a paring mechanism between holes in the dilute limit of doped frustrated Mott insulators. We will see that magnons provide a strong glue in the infinitely repulsive limit of triangular lattice Hubbard model. The strongly attractive hole-magnon interaction is a manifestation of a “counter-Nagaoka” theorem: the single-hole kinetic energy is minimized for an antiferromagnetically ordered state. We will show that the resulting hole-magnon glue is strong enough to bind a second hole and form a hole-hole-magnon three-body bound state. Remarkably, the binding energy of this “composite Cooper pair” is rather strong, while its effective mass still has a moderate value, giving rise to relatively high transition temperature for superconductivity. We will discuss possible experimental realizations of this new mechanism.


 

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