Relaxation of quasi-two-dimensional electrons in a quantizing magnetic field probed by time-resolved cyclotron resonance

Khodaparast, Giti A.; Larrabee, D. C.; Kono, Junichiro; King, D. S.; Chung, S. J.; Santos, M. B.

doi:10.1103/physrevb.67.035307

Cited by 21 publications

(17 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both can influence the screening of the lattice, affecting m*, and the screening of scatterers, as has been reported for low temperature grown GaAs [29,31]. Collective phenomena, however, cannot account for an increase of 30 times.…”

mentioning

confidence: 83%

Enlarged magnetic focusing radius of photoinduced currents in mesoscopic circuits

et al. 2012

View full text Add to dashboard Cite

We exploit GaAs-based quantum point contacts as mesoscopic detectors to analyze the ballistic flow of photogenerated electrons in a two-dimensional electron gas at a perpendicular magnetic field. Whereas charge transport experiments always measure the classical cyclotron radius, we show that this changes dramatically when detecting the photoinduced non-equilibrium current in magnetic fields. The experimentally determined radius of the trajectories surprisingly exceeds the classical cyclotron value by far. Monte Carlo simulations suggest electron-electron scattering as the underlying reason. PACS: 73.23.Ad, 42.82.Fv, 81.07.St, 85.35.Be, 72.20.Dp KEYWORDS. Ballistic optoelectronic quantum transport, nanoscale optoelectronics, nonequilibrium transport, electron-electron scattering 2In the presence of a magnetic field B, propagating charge carriers obey the Lorenz force and move on curved trajectories in the plane perpendicular to the field. The corresponding classical cyclotron radius r cyclo (| |) = |v| | |(1) for a charge q is a measure of its momentum and thus contains both mass m and velocity v of the carrier. Based on Eq. 1, cyclotron resonance experiments on twodimensional electron systems have been used to verify the 2D nature, to determine the components of the effective mass tensor in solids and to obtain information on Fermi contours [1]. However, following Kohn's theorem, the mass measured in cyclotron resonance experiments is expected to be the bare mass, not affected by electron-electron interactions [2]. In magnetic focusing experiments, quantum point contacts (QPCs) have been used both as injectors and detectors to indirectly obtain information on cyclotron trajectories of ballistic currents in two-dimensional electron gases (2DEGs) [3,4,5,6]. At 2DEGs' boundaries, even skipping cyclotron orbits have been visualized using a scanning gate technique [7,8,9,10], and different electron trajectories have been shown to interfere with each other [8,11,12]. The trajectories extracted were in accordance with Eq. (1) and the expected effective mass GaAs * of the GaAs-based circuits.Here, we exploit an optical beam induced current (OBIC) technique to directly analyze the flowpatterns of photogenerated electrons in a 2DEG embedded in an AlGaAs/GaAs quantum well at a perpendicular magnetic field. In contrast to the magnetic focusing results gained from transport experiments, we uncover the magnetic focusing dynamics of photogenerated non-equilibrium excess charge carriers in a 2DEG. A laser locally creates charge carriers at a certain position in the 2DEG, and the ballistic photocurrent of the photogenerated electrons across an adjacent QPC is measured as a function of the laser position [13,14]. This OBIC-technique allows adjusting the excitation position independent of the applied |B|. Thus, it is possible to directly map the magnetic flow patterns of photogenerated electrons in the 2DEG. We observe curved trajectories with a radius being inversely proportional to |B| as expected from Eq. (1). However...

show abstract

mentioning

confidence: 83%

Enlarged magnetic focusing radius of photoinduced currents in mesoscopic circuits

et al. 2012

View full text Add to dashboard Cite

show abstract

“…An earlier measurement on an undoped InSb MQW demonstrated the generation of high density photo-excited carriers in the wells using 800 nm pulses. Selective probe of the conduction band demonstrated carrier relaxation time of ~200 ps [17] . In addition, here we report a two color scheme where NIR pulses used to pump above the bandgap of both Al x In 1-x Sb and InSb layers and the probe pulses were tuned selectively in the vicinity of several interband transitions in the well.…”

Section: Spin Polarized Current In Insb Qwsmentioning

confidence: 99%

Probe of coherent and quantum states in narrow-gap semiconductors in the presence of strong spin-orbit coupling

et al. 2010

View full text Add to dashboard Cite

In light of the growing interest in spin-related phenomena and devices, there is now a renewed interest in the science and engineering of narrow gap semiconductors. They offer several scientifically unique electronic features such as a small effective mass, a large g-factor, a high intrinsic mobility, and large spin-orbit coupling effects. Our studies have been focused on probing and controlling the coherent and quantum states in InSb quantum wells and InMnAs ferromagnetic semiconductors. Our observations are providing new information regarding the optical control of carriers and spins in these material systems. We demonstrated the generation of spin polarized photo-current in an InSb QW where a non-equilibrium spin population has been achieved by using circularly polarized radiation. In addition, the differential transmission measurements in InSb QWs demonstrated that the initial distribution function strongly influences the carrier relaxation dynamics. We employed the polarization-resolved differential transmission as well as the MOKE measurements to provide information on the spin relaxation dynamics in MOVPE grown InMnAs. Our measured T 1 is comparable to the reported measurements in MBE grown InMnAs and several time resolved measurements on InAs.

show abstract

“…The basic parameters, like effective masses and relaxation rates, and essential effects, like magnetoplasmons or polaronic renormalization of resonance, are measured under the thermal equilibrium conditions. To the best of our knowledge, the time-resolved measurements of the cyclotron resonance of electrons after optical excitation (see [6] and references therein) were not performed for the case of ANC regime. Thus, an investigation of a transient magnetoresponse under ultrafast photoexcitation of with a partially inverted distribution is timely now.…”

Section: Introductionmentioning

confidence: 98%

Transient negative cyclotron absorption due to partially‐inverted distribution of photoexcited electrons

Romanets¹,

Vasko²,

Ryzhii³

2008

Phys. Status Solidi (c)

View full text Add to dashboard Cite

The transient magnetoresponse of electrons with partially‐inverted distribution excited by an ultrashort optical pulse in bulk GaAs and InSb is considered. A huge transient amplification of a probe microwave or THz field due to negative cyclotron absorption is described using the kineticequation and the wave equation. A quantum picture of THz emission due to transitions between the Landau levels with different broadenings is suggested. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

show abstract

Relaxation of quasi-two-dimensional electrons in a quantizing magnetic field probed by time-resolved cyclotron resonance

Cited by 21 publications

References 16 publications

Enlarged magnetic focusing radius of photoinduced currents in mesoscopic circuits

Enlarged magnetic focusing radius of photoinduced currents in mesoscopic circuits

Probe of coherent and quantum states in narrow-gap semiconductors in the presence of strong spin-orbit coupling

Transient negative cyclotron absorption due to partially‐inverted distribution of photoexcited electrons

Contact Info

Product

Resources

About