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Jun Xiong

Publications and source records attributed to Jun Xiong.

48 records · Page 3Linked to original sources
arXiv2012

High-Field Shubnikov-de Haas Oscillations in the Topological Insulator Bi$_2$Te$_2$Se

We report measurements of the surface Shubnikov de Haas oscillations (SdH) on crystals of the topological insulator Bi$_2$Te$_2$Se. In crystals with large bulk resistivity ($\sim$4 $Ω$cm at 4 K), we observe $\sim$15 surface SdH oscillations (to the $n$ = 1 Landau Level) in magnetic fields $B$ up to 45 Tesla. Extrapolating to the limit $1/B\to 0$, we confirm the $\frac12$-shift expected from a Dirac spectrum. The results are consistent with a very small surface Lande $g$-factor.

cond-mat.mes-hall↗
arXiv2012

Two-Photon Airy Disk

We report an experimental observation of quantum Airy disk diffraction pattern using an entangled two-photon source. In contrast to the previous quantum lithography experiments where the subwavelength diffraction patterns were observed in the far field limit, we perform the Fraunhofer diffraction experiment with a convex lens. The experimental result shows that the two-photon Airy disk is provided with the super-resolution spot, which surpasses the classical diffraction limit. In particular, the spot size can be well controlled by the focal length, which adapted to optical super-focusing. Our experiment can promote potential application of quantum lithography.

quant-ph↗
arXiv2011

Low carrier concentration crystals of the topological insulator Bi$_2$Te$_2$Se

We report the characterization of Bi$_2$Te$_2$Se crystals obtained by the modified Bridgman and Bridgman-Stockbarger crystal growth techniques. X-ray diffraction study confirms an ordered Se-Te distribution in the inner and outer chalcogen layers, respectively, with a small amount of mixing. The crystals displaying high resistivity ($> 1 \mathrm{Ωcm}$) and low carrier concentration ($\sim 5\times 10^{16}$/cm$^3$) at 4 K were found in the central region of the long Bridgman-Stockbarger crystal, which we attribute to very small differences in defect density along the length of the crystal rod. Analysis of the temperature dependent resistivities and Hall coefficients reveals the possible underlying origins of the donors and acceptors in this phase.

cond-mat.str-el↗
arXiv2011

Effect of hydrostatic pressure on transport in the topological insulator Bi$_2$Te$_2$Se

The Hall coefficient $R_H$ and resistivity $ρ$ of the topological insulator Bi$_2$Te$_2$Se display a number of puzzling features vs. temperature $T$. We propose a model that describes well the non-monotonic variation of $R_H(T)$. A key feature of the model is a chemical potential that is weakly $T$-dependent. From the fit to the model, we infer a "transport" gap $Δ_T$ of 50 mV. We find that hydrostatic pressure $P$ (0-27 kbar) has a pronounced effect on both $R_H$ and $ρ$. We show that these changes arise from decreases in both $Δ_T$ and the hole effective mass under pressure.

cond-mat.mes-hall↗
arXiv2011

Quantum Oscillations in a Topological Insulator Bi$_2$Te$_2$Se with Large Bulk Resistivity (6 $Ω$cm)

We report the observation of prominent Shubnikov-de Haas oscillations in a Topological Insulator, Bi$_2$Te$_2$Se, with large bulk resistivity (6 $Ω$cm at 4 K). By fitting the SdH oscillations, we infer a large metallicity parameter $k_F\ell$ = 41, with a surface mobility ($μ_s\sim$ 2,800 cm$^2$/Vs) much larger than the bulk mobility ($μ_b\sim$ 50 cm$^2$/Vs). The plot of the index fields $B_ν$ vs. filling factor $ν$ shows a $\frac12$-shift, consistent with massless, Dirac states. Evidence for fractional-filling states is seen in an 11-T field.

cond-mat.mes-hall↗
arXiv2009

Phase Reversal Diffraction in incoherent light

Phase reversal occurs in the propagation of an electromagnetic wave in a negatively refracting medium or a phase-conjugate interface. Here we report the experimental observation of phase reversal diffraction without the above devices. Our experimental results and theoretical analysis demonstrate that phase reversal diffraction can be formed through the first-order field correlation of chaotic light. The experimental realization is similar to phase reversal behavior in negatively refracting media.

quant-ph↗
arXiv2008

Spatial Interference: From Coherent To Incoherent

It is well known that direct observation of interference and diffraction pattern in the intensity distribution requires a spatially coherent source. Optical waves emitted from portions beyond the coherence area possess statistically independent phases, and will degrade the interference pattern. In this paper we show an optical interference experiment, which seems contrary to our common knowledge, that the formation of the interference pattern is related to a spatially incoherent light source. Our experimental scheme is very similar to Gabor's original proposal of holography[1], just with an incoherent source replacing the coherent one. In the statistical ensemble of the incoherent source, each sample field produces a sample interference pattern between object wave and reference wave. These patterns completely differ from each other due to the fluctuation of the source field distribution. Surprisingly, the sum of a great number of sample patterns exhibits explicitly an interference pattern, which contains all the information of the object and is equivalent to a hologram in the coherent light case. In this sense our approach would be valuable in holography and other interference techniques for the case where coherent source is unavailable, such as x-ray and electron sources.

physics.optics↗
arXiv2007

Nonlocal Double-Slit Interference with Pseudothermal Light

We perform a nonlocal double-slit interference experiment with pseudothermal light. The experimental result exhibits a typical double-slit interference fringe in the intensity correlation measurement, in agreement with the theoretical analysis by means of the property of the second-order spatial correlation of field.

quant-ph↗
arXiv2007

Complementarity in a macroscopic observation

Complementarity is usually considered as a phenomenon of microscopic systems. In this paper we report an experimental observation of complementarity in the correlated double-slit interference with a pseudothermal light source. The thermal light beam is divided into test and reference beams which are correlated with each other. The double-slit is set in the test arm, and the interference pattern can be observed in the intensity correlation between the two arms. The experimental results show that the disappearance of interference fringe depends on whether which-path information is gained through the reference arm. The experiment therefore witnesses the complementarity occurring in a macroscopic system.

quant-ph↗
arXiv2005

Sub-Rayleigh resolution of interference pattern with independent laser beams

We propose a new scheme to achieve sub-Rayleigh resolution of interference pattern with independent laser beams. We perform an experimental observation of a double-slit interference with two orthogonally polarized laser beams. The resolution of the interference pattern measured by a two-photon detection is doubled provided the two beams illuminate the double-slit with certain incident angles. The scheme is simple and can be in favor of both high intensity and perfect visibility.

physics.optics↗
arXiv2004

Geometrical Optics in Coincidence Imaging System

We discuss the geometrical optics of coincidence imaging for two kinds of spatial correlations which are related to a classical thermal light source and a two-photon quantum entangled state.

quant-ph↗