1. Department of Mechanical Engineering, University of California, Berkeley, CA, USA
2. São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos 13560-970, São Paulo, Brazil
3. Department of Mechatronics Engineering, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, HuBei 430074, China
4. Department of Physics, University of California at Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, Kavli Energy NanoSciences Institute, Berkeley, CA 94720, USA
5. Department of Physics, Goa University, Taleigao Plateau, Goa, 403206, India
6. Department of Physics, Chaman Lal Mahavidyalaya, Haridwar, India