1. Instituto de Fisica, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro, RJ, Brazil
2. The Blackett Laboratory, Physics Department, Imperial College London, London SW7 2AZ, United Kingdom
3. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
4. Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
5. Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, People’s Republic of China