Controlling charge and spin faster than a cycle of light (Prof. R. Huber)

  • Datum: 08.07.2014
  • Uhrzeit: 12:30 - 12:30
  • Vortragende(r): Professor Rupert Huber, Universität Regensburg
  • Raum: Herbert Walther Lecture Hall
  • Gastgeber: MPQ
The physical properties of condensed matter are often caused by ultrafast phenomena involving low-energy elementary excitations, such as lattice vibrations, spin pre­ces­sion, plasmons, or superconducting energy gaps.

Phase-locked few-cycle pulses in the terahertz and mid-infrared spectral domain in combination with field-sensitive detectors have been able to monitor these excitations directly with a time resolution faster than an oscillation period of the carrier wave. Next-generation high-intensity terahertz sources have now opened the exciting possibility to explore condensed matter in an unprecedented regime of atomically strong electric and magnetic terahertz biasing. We show that terahertz fields of up to 11 GV/m can accelerate electrons in bulk semiconductors to perform complete Bloch oscillation cycles within half an oscillation period of the infrared drive field. The concomitant magnetic field component allows us to control spins in magnetically ordered solids on the sub-cycle scale. Our experiments challenge latest quantum theories and spark hope for superfast electronics and magnetic storage devices at multi-terahertz clock rates.

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