Optical Pump/ Optical Probe and Electronic Transport

Pump/probe experiments allow the study of the spin dynamics during carrier transport across materials with strong and electrically tunable spin-orbit interaction. Our optical pump / optical probe setup uses a picosecond Mira laser from Coherent, pumped by a solid-state Verdi also from Coherent, motorized mirrors to control pump-probe distance on the sample, motorized lenses to improve the focusing of the laser on the sample surface, a long mechanical delay line, and an Oxford Spectromag cryostat for magnetic fields up to 7 T and low temperatures down to 1.2 K. The detection consists of a polarization bridge with balanced photodiodes and both pump and probe are modulated (with photoelastic modulator and chopper) and locked-in two different amplifiers. The Spectromag cryostat can be also used for electronic transport measurements including illumination with microwaves.




Selected publications
- Interaction-controlled transport in a two-dimensional massless-massive Dirac system: Transition from degenerate to nondegenerate regimes. Phys. Rev. Research 6, 023121 (2024).
- Engineering topological phases in triple HgTe/CdTe quantum wells. Scientific Reports 12, 2617 (2022).
- Multiple crossing of Landau levels of two-dimensional fermions in double HgTe quantum wells. Phys. Rev. B 103, 035302 (2021).
- Phonon drag thermoelectric phenomena in mesoscopic two-dimensional conductors: Current stripes, large Nernst effect, and influence of electron-electron interaction. Phys. Rev. B 102, 195301 (2020).
- Two-dimensional topological insulator state in double HgTe quantum well. Phys. Rev. B 101, 241302 Rapid Communications (2020).
- Electrical control of spin relaxation anisotropy during drift transport in a two-dimensional electron gas. Phys. Rev. B 102, 125305 (2020).
- Acceleration of the precession frequency for optically-oriented electron spins in ferromagnetic/semiconductor hybrids. Scientific Reports 9, 7294 (2019).
- Robustness of spin polarization against temperature in multilayer structure: Triple quantum well. J. App. Phys. 123, 214306 (2018).
- Gate control of the spin mobility through the modification of the spin-orbit interaction in two-dimensional systems. Phys Rev. B 95, 245315 (2017).
- Large anisotropic spin relaxation time of exciton bound to donor states in triple quantum wells. J. App. Phys. 121, 205703 (2017).
- Spin drift and diffusion in one- and two-subband helical systems. Phys. Rev. B 95, 125119 (2017).
- Macroscopic transverse drift of long current-induced spin coherence in two-dimensional electron gases. Phys. Rev. B 94, 045305 (2016).
- Current-controlled Spin Precession of Quasi-Stationary Electrons in a Cubic Spin-Orbit Field. Phys. Rev. Lett. 116, 196802 (2016).
- Long-lived nanosecond spin coherence in high-mobility 2DEGs confined in double and triple quantum wells. J. Appl. Phys. 119, 215701 (2016).
- Resonant control of the electrically-induced spin polarization by periodic excitation. Phys. Rev. B 90, 041302 Rapid Communications (2014).              
- Observation of the intrinsic spin Hall effect in a two-dimensional electron gas. Phys. Rev. B 88, 161305 Rapid Communications (2013).
- Linear and nonlinear transport in a small charge-tunable open quantum ring. Phys. Rev. B 84, 075332 (2011).
- Temperature induced spin coherence dissipation in quantum dots. Phys. Rev. B 78, 041303 (2008). Rapid Communications, Editor’s Suggestion and VJNANO July 2008.
- Determination of spin polarization in InAs/GaAs self-assembled quantum dots, Appl. Phys. Lett. 92, 132106 (2008).  VJNANO April 2008.
- Robust manipulation of electron spin coherence in an ensemble of singly charged quantum dots. Phys. Rev. B 75, 233301 (2007). Brief Report.
- Landé g Tensor in Semiconductor Nanostructures. Phys. Rev. Lett. 97, 236402 (2006). VJNANO December 2006.