Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Artificial Molecules: Antibonding Molecular Ground State for Holes Revealed | Nanoscale Res Lett 2009 4 191-192 DOI s11671-008-9220-7 NANO SPOTLIGHTS Artificial Molecules Antibonding Molecular Ground State for Holes Revealed Published online 25 November 2008 to the author 2008 Semiconductor quantum dots have long been described as artificial atoms because they have discrete energy states analogous to the energy levels of natural atoms. In recent years it has become possible to create coupled pairs of quantum dots that are analogous to natural diatomic molecules. These artificial molecules have received a great deal of attention because of the potential applications in novel optoelectronic and spintronic devices including the possibility of scalable implementations of quantum information processing. Just as in natural diatomic molecules tunneling of electrons or holes between the two dots creates delocalized molecular orbitals. In natural diatomic molecules the molecular ground state has bonding orbital character and the first excited molecular state has antibonding character. Artificial quantum dot molecules were believed to behave in a similar way. However recently Dr. Doty from the University of Delaware Dr. Climente from Universitat Jaume I Castellon Spain and their collaborators in Canada and the US have experimentally verified and explained the existence of an antibonding molecular ground state for holes in artificial quantum dot molecules. The coherent coupling of quantum dots leads to the formation of delocalized molecular orbitals that appear in photoluminescence spectra under electric fields as ant crossings. The orbital character of the molecular states cannot be measured at zero magnetic field. However a recent discovery by Doty and coworkers at the Naval Research Lab revealed that when a magnetic field was applied the resonant changes in the Zeeman splitting that depended on the orbital character of the molecular states appeared. Using these changes to identify the molecular orbital character Doty and coworkers .
