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Title: Nonlinear terahertz response of HgTe/CdTe quantum wells

Without breaking the topological order, HgTe/CdTe quantum wells can have two types of bulk band structure: direct gap type (type I) and indirect gap type (type II). We report that the strong nonlinear optical responses exist in both types of bulk states under a moderate electric field in the terahertz regime. Interestingly, for the type II band structure, the third order conductivity changes sign when chemical potentials lies below 10 meV due to the significant response of the hole excitation close to the bottom of conduction band. Negative nonlinear conductivities suggest that HgTe/CdTe quantum wells can find application in the gain medium of a laser for terahertz radiation. The thermal influences on nonlinear optical responses of HgTe/CdTe quantum wells are also studied.
Authors:
 [1] ;  [2] ; ;  [3]
  1. School of Physics and Electronics, Hunan University, Changsha 410082 (China)
  2. (Australia)
  3. School of Physics, University of Wollongong, Wollongong, New South Wales 2522 (Australia)
Publication Date:
OSTI Identifier:
22489142
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CADMIUM TELLURIDES; ELECTRIC FIELDS; EXCITATION; HOLES; LASERS; MERCURY TELLURIDES; MILLI EV RANGE; NONLINEAR PROBLEMS; POTENTIALS; QUANTUM WELLS; TOPOLOGY