Projects / Programmes
Femtosecond time-resolved scanning tunneling electron microscopy of complex materials
| Code |
Science |
Field |
Subfield |
| 1.02.01 |
Natural sciences and mathematics |
Physics |
Physics of condesed matter |
| Code |
Science |
Field |
| P002 |
Natural sciences and mathematics |
Physics |
| Code |
Science |
Field |
| 1.03 |
Natural Sciences |
Physical sciences |
TaS2, tunneling microscopy, THz pulses, femtosecond time resolution, spatially nonhomogeneous systems, atomic spatial resolution
Researchers (13)
Organisations (2)
Abstract
We propose a project to build a low-temperature time-resolved pump-probe scanning tunneling microscope (STM) for investigating the real-time femtosecond dynamics of elementary excitations in complex materials with atomic resolution. THz pulses will be used to excite plasmonic excitations in the metal STM tip, thus temporarily enhancing (gating) the tunneling current, and thus allowing us to probe the photoexcited dynamics on a sub-picosecond timescale. The microscope will be made to operate at temperatures down to 4.2 kelvin and will be implemented inside an Omicron 4-probe LT-STM system and an external THz source. The technique will allow time-dynamics to be investigated in spatially non-homogeneous systems for the first time, thus opening the way to address some long-standing fundamental problems in the dynamics of complex condensed matter systems. To demonstrate operation of our ultrafast STM (USTM) machine, we will perform exploratory experiments on a number of currently topical materials.
Significance for science
Introduction of a new research field in Slovenia
The succesful and timely completion of the project would be of world class importance. Currently we have a good chance to have the world's first operational low-temperature (LT) ultrafast scanning tunneling microscope (USTM), enabling for the first time unprecedented studies of the dynamics of electrons and lattice excitations with temporal resolution limited by the 1-2 THz gating pulse length. Two other groups have demonstrated room temperature operation, but the construction of a low-temperature cryostat is much more demanding than the demonstration of the technique at room temperature. We have already published STM studies of samples excited by femtosecond pulses at 4K, so we currently have a lead in LT operation and THz gating would bring this to culmination.
In effect, it would be an ultrafast spectrally resolved movie camera, with a spatial resolution of individual orbitals. This would open the way to unprecedented new insights into correlated electron and other complex systems which typically exhibit functional properties at low temperatures. It would also demonstrate the power of time-resolved studies with USTM, and filling in an important shortcoming of techniques such as ultrafast angle resolved photoemission (U-ARPES) which have very limited spatial resolution (currently )20 nm with synchrotron radiation). Successully executed project would constitute an introduction to an entirely new research area in Slovenia and could lead to the establishment of a research center or laboratory. With manufacturing the device, we would acquire a lot of new practical knowledge and information, which would help to increase the qualifications of the research staff.
Significance for the country
Infrastructure
The development of the U-STM instrument would be an extremely important addition to the infrastructure facilities in Slovenia. Merging activities around high-tech equipment provides further enrichment of knowledge. With the flow of young researchers and different industrial projects, this knowledge would be directly available for realizaton of new technologies.
A commercial device, knowledge which leads to establishment of a new enterprise
We are expecting to construct a commercially attractive device by 2018. We can offer it to the market within existing center of excelence Nanocenter or within a new startup company, but certainly a Slovenian company. The market for such a device, as an add-on to the commercial Scienta-Omicron nanoprobe LT, is global. Such add-on instruments are common for this device, and many manufacturers are already offering them.
Most important scientific results
Final report
Most important socioeconomically and culturally relevant results
Final report
