1. Department of Physics, Queens College of The City University of New York, Queens, New York 11367, USA
2. Department of Electrical Engineering, City College of The City University of New York, New York, New York 10031, USA
3. Department of Physics, City College of The City University of New York, New York, New York 10031, USA
4. The Graduate Center of The City University of New York, New York, New York 10016, USA