2010 June

New highlight from the EPJD

Thursday, 24th June 2010Publication highlights

An article from the Fritz Haber Institute’s Molecular Physics department has been selected as a May Highlight in the European Physical Journal D. The Berlin scientists describe a new hand-held Stark decelerator based on wire electrodes, which is suitable for cold atom and cold molecule experiments that require ultra-high vacuum conditions. A brief report can also be found in the Sept/Oct issue of Europhysics News.

(Published Online: 26 May 2010 |Eur. Phys. J. D, 59, 179 ).

Further information: Adela Marian

The missing link found: A classical diffraction anomaly observed in atomic optics

Monday, 21st June 2010Publication highlights

Researchers at the Fritz Haber Institute have completed the analogy between classical optics and atomic optics by experimentally observing the so-called Rayleigh-Wood anomalies. The diffraction phenomena of dark and bright bands in a spectrum, first observed by Wood and later explained by Rayleigh, is a resonance effect from light passing near the surface of the grating. Wave-particle-duality allows for the observation of this classical optical effect with atomic matter waves. These observations have a potential value in improving the understanding of atom-surface scattering processes. Their findings have been published in the journal Physical Review Letters. more

(Published: 18 June 2010 | Phys. Rev. Lett., 104, 240404).

Further information: Bum Suk Zhao and Wieland Schöllkopf

“Plasmaron” quasiparticles observed in graphene

Monday, 14th June 2010Publication highlights

Fig: Bostwick et al.

A novel kind of quasiparticles, i.e., charge carriers coupled to other elementary excitations, has been identified in graphene, the single layer of hexagonally coordinated carbon, by an international collaboration from the US, Germany, Italy and Iran.  Their experimental data and theoretical analysis have identified so-called plasmarons, which arise from a coupling between graphene’s charge carriers (electrons and holes) and the density oscillations of the charge carriers, that is, oscillations that move like sound waves through the “liquid” of all carriers in the material. This coupling creates the plasmarons, which have been theoretically predicted already in the 1960’s. In the current work, plasmarons are identified through their influence on the electronic structure of graphene. Such findings not only aid in the understanding of the astonishing physical properties of graphene – properties which have caused a storm of excitement in solid state and materials science in recent years – but also signal the approaching realization of using such particles in future electronic devices in a field referred to as “plasmonics”.  The international team reports their findings and discusses their implications in an article entitled “Observation of Plasmarons in Quasi-Freestanding Doped Graphene” appearing in the journal Science. more

(Published: 21 May 2010 | Science, 328, 999).

Further information: Karsten Horn