PIRSA:10090105

Quantum-spin-Hall-like phenomena and duality between order parameters in graphene

Ryu, S. (2010). Quantum-spin-Hall-like phenomena and duality between order parameters in graphene. Perimeter Institute. https://pirsa.org/10090105

Ryu, Shinsei. Quantum-spin-Hall-like phenomena and duality between order parameters in graphene. Perimeter Institute, Sep. 28, 2010, https://pirsa.org/10090105 

          @misc{ pirsa_PIRSA:10090105,
            doi = {10.48660/10090105},
            url = {https://pirsa.org/10090105},
            author = {Ryu, Shinsei},
            keywords = {Cosmology},
            language = {en},
            title = {Quantum-spin-Hall-like phenomena and duality between order parameters in graphene},
            publisher = {Perimeter Institute},
            year = {2010},
            month = {sep},
            note = {PIRSA:10090105 see, \url{https://pirsa.org}}
          }

Shinsei Ryu

University of Illinois at Urbana-Champaign (UIUC)

Talk number
PIRSA:10090105
Collection
Talk Type
Subject
Abstract
The quantum spin Hall effect relates seemingly unrelated degrees of freedom, i.e., charge and spin degrees of freedom. We will discuss such "duality" can be extended to much wider class of quantum numbers, and the corresponding order parameters. In particular, two valleys in graphene can be viewed as an SU(2) pseudo spin degree of freedom, which turns out to be "dual" to the charge degree of freedom, pretty much in the same way as spin in the quantum spin Hall effect is closely tied with charge. I.e., graphene can host "the quantum valley Hall effect" (QVHE). We will show that one of the best venues to observe the QVHE in graphene is actually superconductivity that can be induced in graphene by proximity effect, say, where passing supercurrent in one direction induces accumulation of pseudo spin ("valley spin") at the boundary of graphene sample. We will also discuss the "inverse QVHE" as a possible scenario to explain the highly resistive state found in N=0 Landau level in graphene in a high magnetic field.