Anisotropic exchange interaction induced by a single photon in semiconductor microcavities

We investigate coupling of localized spins in a semiconductor quantum dot embedded in a microcavity. The lowest cavity mode and the quantum dot exciton are coupled and close in energy, forming a polariton. The fermions forming the exciton interact with localized spins via exchange. Exact diagonalization of a Hamiltonian in which photons, spins, and excitons are treated quantum mechanically shows that a single polariton induces a sizable indirect anisotropic exchange interaction between spins. At sufficiently low temperatures strong ferromagnetic correlations show up without an appreciable increase in exciton population. In the case of a (Cd,Mn)Te quantum dot, Mn-Mn ferromagnetic coupling is still significant at 1 K: spin-spin correlation around 3 for exciton occupation smaller than 0.3. We find that the interaction mediated by photon-polaritons is 10 times stronger than the one induced by a classical field for equal Rabi splitting.

Optical probing of spin fluctuations of a single paramagnetic Mn atom in a semiconductor quantum dot

We analyzed the photoluminescence intermittency generated by a single paramagnetic spin localized in an individual semiconductor quantum dot. The statistics of the photons emitted by the quantum dot reflect the quantum fluctuations of the localized spin interacting with the injected carriers. Photon correlation measurements, which are reported here, reveal unique signatures of these fluctuations. A phenomenological model is proposed to quantitatively describe these observations, allowing a measurement of the spin dynamics of an individual magnetic atom at zero magnetic field. These results demonstrate the existence of an efficient spin-relaxation channel arising from a spin exchange with individual carriers surrounding the quantum dot. A theoretical description of a spin-flip mechanism involving spin exchange with surrounding carriers gives relaxation times in good agreement with the measured dynamics.

Coherent-light emission from exciton condensates in semiconductor quantum wells

We show that a quasi-two dimensional condensate of optically active excitons emits coherent light even in the absence of population inversion. This allows an unambiguous and clear experimental detection of the condensed phase. We prove that, due to the exciton–photon coupling, quantum and thermal fluctuations do not destroy condensation at finite temperature. Suitable conditions to achieve condensation are temperatures of a few K for typical exciton densities and the use of a pulsed and preferably circularly polarized, laser.

Intrinsic spin noise in MgO magnetic tunnel junctions

We consider two intrinsic sources of noise in ultra-sensitive magnetic field sensors based on MgO magnetic tunnel junctions, coming both from 25 Mg nuclear spins (I = 5/2, 10% natural abundance) and S = 1 Mg-vacancies. While nuclear spins induce noise peaked in the MHz frequency range, the vacancies noise peaks in the GHz range. We find that the nuclear noise in submicron devices has a similar magnitude than the 1/f noise, while the vacancy-induced noise dominates in the GHz range. Interestingly, the noise spectrum under a finite magnetic field gradient may provide spatial information about the spins in the MgO layer.

Theory of many-particle correlations and optical properties of semiconductor quantum dots : photons and quantum dots

Otto-von-Guericke-Universität Magdeburg, Fakultät für Naturwissenschaften, Dissertation, 2016

Bibliography on semiconductor nuclear radiation detectors /

"December 6, 1960."

Bibliography on semiconductor nuclear radiation detectors /

Included are 464 selected references on the theory, manufacture, properties, performance, and utliization of semiconductor materials for the detection of nuclear radiation. Reports and open literature references are covered through January 1962.

Zn₃P₂ as an improved semiconductor for photovoltaic solar cells : ninth quarterly report for September 1 - November 31, 1980 /

"Work Performed Under Contract No. AC02-77CH00178."

Design of the program-controlled semiconductor and printed circuit board test console /

"October 21, 1963"

Molecular bandpass amplifiers. Contract AF33(616)-7252. Interim scientific report no. 1- [of the] Development Laboratory, Semiconductor Division, Hughes Aircraft Co.

Mode of access: Internet.

All semiconductor distributed aerospace processor/memory study /

"August 1973."

Semiconductor measurement technology : techniques for measuring the integrity of passivation overcoats on integrated circuits /

Mode of access: Internet.

Semiconductor /

Mode of access: Internet.

Semiconductor detectors in medicine, March 8-9, 1973, presented by Nuclear Medicine Division, Department of Radiology, University of California School of Medicine and Continuing Education in Health Sciences, University of California, San Francisco, California, supported in part by KeVex Corporation, Burlingame, California [et al.

Mode of access: Internet.