arXiv subjects

Ran Salem

Publications and source records attributed to Ran Salem.

4 recordsLinked to original sources

arXiv2025

Pressure Induced Anomalous Metal in the Vicinity of the Superconductor Insulator Transition

The Superconductor-to-Insulator Transition (SIT) in two-dimensional superconductors occurs due to a competition between superconductivity, quantum interferences, Coulomb interactions and disorder. Despite extensive theoretical and experimental investigation, the SIT remains an active research area due to the potential for exotic phases near the transition. One such phase is the Anomalous Metal, which has been claimed to exist between the insulating and superconducting states. This elusive phase, which is not consistent with current theories, is under heavy deliberations nowadays. We present an experimental study of the effect of high pressure on thin films of amorphous indium oxide. Our results show that pressure induces a series of transitions from a Bose insulator through a superconducting phase, metallic phases and finally to a conventional insulator. We suggest that our findings reaffirm the existence of a two-dimensional metal close to the SIT and show that its occurrence requires relatively strong coupling between regions that are weakly superconducting.

cond-mat.supr-con↗

arXiv2015

Image analysis as an improved melting criterion in laser-heated diamond anvil cell

The precision of melting curve measurements using laser-heated diamond anvil cell (LHDAC) is largely limited by the correct and reliable determination of the onset of melting. We present a novel image analysis of speckle interference patterns in the LHDAC as a way to define quantitative measures which enable an objective determination of the melting transition. Combined with our low-temperature customized IR pyrometer, designed for measurements down to 500K, our setup allows studying the melting curve of materials with low melting temperatures, with relatively high precision. As an application, the melting curve of Te was measured up to~$\rm35\,GPa$. The results are found to be in good agreement with previous data obtained at pressures up to~$\rm10\,GPa$.

cond-mat.mtrl-sci↗

arXiv2014

Phase space tomography of cold-atoms dynamics in a weakly corrugated potential

We demonstrate tomographic reconstruction of the phase space distribution of atoms oscillating in a harmonic trap with weak potential corrugation caused by nanoscale imperfections in an atom chip. We find that deformations in these distributions are highly sensitive to anharmonic components of the potential. They are explained in terms of angular velocity dispersion of isoenergetic phase space trajectories. We show that the method is applicable for probing classical and quantum dynamics of cold atoms, and we note its importance for future technological applications.

quant-ph↗

arXiv2002

Exchange Based Noise Spectroscopy of a Single Precessing Spin with STM

ESR-STM is an emerging technique which is capable of detecting the precession of a single spin. We discuss the mechanism of ESR-STM based on a direct exchange coupling between the tunneling electrons and the local precessing spin S. We claim that since the number of tunneling electrons in a single precessing period is small (~20) one may expect a net temporary polarization within this period that will couple via exchange interaction to the localized spin. This coupling will randomly modulate the tunneling barrier and create a dispersion in the tunneling current which is a product of a Larmor frequency component due to the precession of the single spin and the dispersion of the spin of the tunneling electrons. This noise component is spread over the whole frequency range for random white noise spin polarization of electrons. In opposite case the power spectrum of the spins of the tunneling electrons has a peak at zero frequency an elevated noise in the current at omega_L will appear. We discuss the possible source of this spin polarization. We find that for relevant values of parameters signal to noise ratio in the spectral characteristic is 2-4 and is comparable to the reported signal to noise ratio. The magnitude of the current fluctuation is a relatively weak increaing function of the DC current and the magnetic field. The linewidth produced by the back action effect of tunneling electrons on the precessing spin is also discussed.

cond-mat.mes-hall↗