[1
]Department of Materials Science and EngineeringNational Tsing Hua University Hsinchu
30013 Taiwan
[2
]Department of PhysicsNational Sun Yat‐Sen University Kaohsiung 80424 Taiwan
[3
]Frontier Research Center on Fundamental and Applied Sciences of MattersNational Tsing
Hua University Hsinchu 30013 Taiwan
[4
]Physics DivisionThe National Center for Theoretical Science Hsinchu 30013 Taiwan