Journal Club do DFMT
À Comunidade do IFUSP:
Comunicamos, em nome dos organizadores, o adiamento do próximo Journal Club para o dia 26 de abril de 2017.
Secretaria do DFMT
Journal Club do Departamento de Física dos Materiais e Mecânica
Nesta semana a pós-graduanda Dimy Nanclares Fernandes Sanches, do Grupo Teórico de Materiais, apresentará o artigo
Controlled Finite Momentum Pairing and Spatially Varying Order Parameter in Proximitized HgTe Quantum Wells
Sean Hart et al.
Nature Physics 13 87 (2017)
Conventional s-wave superconductivity arises from singlet pairing of electrons with opposite Fermi momenta, forming Cooper pairs with zero net momentum. Recent studies have focused on coupling s-wave superconductors to systems with an unusual configuration of electronic spin and momentum at the Fermi surface,
where the nature of the paired state can be modified and the system may even undergo a topological phase transition. Here we present measurements and theoretical calculations of HgTe quantum wells coupled to aluminium or niobium superconductors and subject to a magnetic field in the plane of the quantum well.
We find that this magnetic field tunes the momentum of Cooper pairs in the quantum well, directly reflecting the response of the spin-dependent Fermi surfaces. In the high electron density regime, the induced superconductivity evolves with electron density in agreement with our model based on the Hamiltonian of Bernevig, Hughes and Zhang. This agreement provides a quantitative value for g_Q=vF, where g_Q is the effective g-factor and vF is the Fermi velocity. Our new understanding of the interplay between spin physics and superconductivity introduces a way to spatially engineer the order parameter from singlet to triplet
pairing, and in general allows investigation of electronic spin texture at the Fermi surface of materials.
Horário: às 12h10min
Local: Sala de Seminários José Roberto Leite - Edifício Alessandro Volta (bloco C)