Ref HAL: hal-04344232_v1
Ref Arxiv: 2311.17638
Ref INSPIRE: 2727878
Ref. & Cit.: NASA ADS
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We study the resurgent structure of the refined topological string partition function on a non-compact Calabi-Yau threefold, at large orders in the string coupling constant $g_s$ and fixed refinement parameter $b$. For $b\neq 1$, the Borel transform admits two families of simple poles, corresponding to integral periods rescaled by $b$ and $1/b$. We show that the corresponding Stokes automorphism is expressed in terms of a generalization of the non-compact quantum dilogarithm, and we conjecture that the Stokes constants are determined by the refined DT invariants counting spin-$j$ BPS states. This jump in the refined topological string partition function is a special case (unit five-brane charge) of a more general transformation property of wave functions on quantum twisted tori introduced in earlier work by two of the authors. We show that this property follows from the transformation of a suitable refined dual partition function across BPS rays, defined by extending the Moyal star product to the realm of contact geometry.

Ref HAL: hal-04313143_v1
DOI: 10.1016/j.matlet.2023.135230
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Pure and Aluminum doped Zinc Oxide Nanoparticles (AZO NPs) with various doping concentrations were synthesized using an original aqueous chemical process under atmospheric pressure and moderate temperature, using only deionized water as a solvent with a filtration step followed by heat treatment.The X-Ray Diffraction (XRD), Raman and Field Emission Scanning Electron Microscopy- Energy-Dispersive X-ray Spectroscopy (FESEM-EDS) analysis of nanoparticles reveals a hexagonal wurtzite structure, with a size around 60 nm and the presence of aluminum in our samples. Optical investigations demonstrate that the material is of high quality, with few deep structural defects, since Photoluminescence (PL) is largely dominated by excitonic emission at low temperatures.

DOI: 10.1073/pnas.2300923120

Ref HAL: hal-04304349_v1
DOI: 10.1109/irmmw-thz57677.2023.10298862
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We report on the emission of Terahertz radiation from Landau quantized Dirac electrons in HgTe/CdHgTe based quantum wells. We show that this cyclotron emission is continuously tunable with magnetic field from 500 GHz up to 2.5 THz. Moreover, given the relativistic nature of charge carriers, the cyclotron mass and therefore the emitted frequency are also tunable with the electron density. These results pave the way for the long-awaited Landau laser which could additionally be tunable by a gate voltage with a fixed magnetic field.

Ref HAL: hal-04304328_v1
DOI: 10.1038/s41598-023-36957-w
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We report on the effects of visible light on the low temperature electronic properties of the spinpolarized two dimensional electron system (2DES) formed at the interfaces between LaAlO 3 , EuTiO 3 and (001) SrTiO 3. A strong, persistent modulation of both longitudinal and transverse conductivity was obtained using light emitting diodes (LEDs) with emissions at different wavelengths in the visible spectrum range. In particular, Hall effect data show that visible light induces a non-volatile electron filling of bands with mainly 3d xz,yz character, and at the same time an enhancement of the anomalous Hall effect associated to the magnetic properties of the system. Accordingly, a suppression of the weak-anti localization corrections to the magneto-conductance is found, which correlates with an enhancement of the spin-polarization and of the ferromagnetic character of 2DES. The results establish the LED-induced photo-doping as a viable route for the control of the ground state properties of artificial spin-polarized oxide 2DES.

Ref HAL: hal-04304435_v1
Ref Arxiv: 2308.13440
DOI: 10.48550/arXiv.2308.13440
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By using the self-consistent Born approximation, we investigate disorder effect induced by shortrange impurities on the band-gap of a seminal two-dimensional (2D) system, whose phase diagram contains trivial, single-band-inverted and double-band-inverted states. Following the density-ofstates (DOS) evolution, we demonstrate multiple closings and openings of the band-gap with the increase of the disorder strength. Calculations of the spectral function describing the quasiparticles at the Γ point of the Brillouin zone evidence that the observed band-gap behavior is unambiguously caused by the topological phase transitions due to the mutual inversions between the first and second electron-like and hole-like subbands. We also find that an increase in the disorder strength in the double-inverted state always leads to the band-gap closing due to the overlap of the tails of DOS from conduction and valence subbands.