Prof. Averitt and colleagues published in Nature
July 19, 2012
Richard Averitt and colleagues have published a letter in Nature entitled “Terahertz-field-induced insulator-to-metal transition in vanadium dioxide metamaterial”. This work is a collaboration with Prof. Keith Nelson’s group at M.I.T., Prof. Stuart Wolf’s group at the University of Virginia, Prof. Xin Zhang at B.U., and Prof. Fiorenzo Omenetto at Tufts. The lead authors are Boston University graduate student Mengkun Liu (now a postdoc at UCSD) and M.I.T. graduate student Harold Hwang.
This work demonstrates that it is possible to drive the insulator-to-metal transition in vanadium dioxide (VO2) – a canonical correlated electron material – on a picosecond timescale using high-field terahertz pulses. To achieve the required fields, metamaterial field enhancement was achieved by directly depositing split ring resonators on the VO2. At the highest fields of approximately 4 MV/cm, irreversible damage occurs as shown in the figure. This novel approach provides a powerful platform to investigate low-energy dynamics in condensed matter and demonstrates that integration of metamaterials with complex matter is a viable pathway to realize functional nonlinear electromagnetic composites.
Image of a metamaterial split ring resonator that is 75 um X 75 um with 1.5 um gaps. Within the gaps strong field enhancement of incident terahertz radiation leads to a rapid increase in the energy density inducing a field-driven insulator-to-metal transition. The field enhancement and resultant phase transition occur on an extreme subwavelength scale. The white regions are damage that occur at the highest incident field.