Solid State Physics Laboratory

About: Solid State Physics Laboratory is a facility organization based out in Delhi, India. It is known for research contribution in the topics: Quantum dot & Dielectric. The organization has 1754 authors who have published 2597 publications receiving 50601 citations.

EPR studies of some thick film ferrates, aluminates and their correlation with humidity sensitivity

Abstract: Ceramic types of humidity sensors using aluminates and ferrates have attracted attention of workers as stable sensors. It is expected that there are some active centers on the surface of the sensors which are responsible to break the water vapor molecule in to H3O+ and OH− ions. These active centers can be unpaired spins or dangling bonds which can be measured using electron paramagnetic resonance (EPR). In the present paper, the dangling bond density of various samples of magnesium aluminates, magnesium ferrates and their mixtures prepared at different temperatures is monitored and correlated with the sensitivity of the humidity sensor prepared. It is found that the sensitivity is increasing as the dangling bond density increases.

Lateral p − n Junction in an Inverted InAs / GaSb Double Quantum Well

Abstract: We present transport measurements on a lateral p-n junction in an inverted InAs/GaSb double quantum well at zero and nonzero perpendicular magnetic fields At a zero magnetic field, the junction exhibits diodelike behavior in accordance with the presence of a hybridization gap With an increasing magnetic field, we explore the quantum Hall regime where spin-polarized edge states with the same chirality are either reflected or transmitted at the junction, whereas those of opposite chirality undergo a mixing process, leading to full equilibration along the width of the junction independent of spin These results lay the foundations for using p-n junctions in InAs/GaSb double quantum wells to probe the transition between the topological quantum spin Hall and quantum Hall states

Low-frequency Raman spectroscopy of alkali-borate glasses

Abstract: Low-frequency Raman spectra of glasses of the types (B 2 O 3 ) 1− x (Li 2 O) x , (B 2 O 3 ) 1− x (Rb 2 O) x and (B 2 O 3 ) 1 − x − y (Li 2 O) x -(Li 2 Cl 2 ) y are presented. The temperature-reduced spectra show a peak at 50 cm −1 and a peak at about 130 cm −1 . The peak at 50 cm −1 appears to be a common property of oxide glasses and arises because the limited structural correlation length of the glass network causes a non-zero maximum of the frequency-dependent Raman coupling coefficient. The 130 cm −1 band can be attributed to librational modes of BO 3 and BO 4 units. For v-B 2 O 3 , a structural correlation length equal to the size of a pair of BO 3 triangles is found. Addition of alkali oxide leads to a decrease of this correlation length. The extra oxygens are mostly incorporated in BO 4 units but larger ions such as Rb + will also enhance the number of non-bridging oxygens. Addition of LiCl does not produce major changes in the Raman spectra and consequently does not change the ratio of the numbers of BO 3 and BO 4 units. The Cl − ions are incorporated in interstitial vacancies of the network, which leads to an expansion of the B-O network structure.

Aharonov-Bohm oscillations in p-type GaAs quantum rings

Abstract: We have explored phase coherent transport of holes in two p-type GaAs quantum rings with orbital radii 420 and 160 nm fabricated with AFM oxidation lithography. Highly visible Aharonov–Bohm (AB) oscillations are measured in both rings, with an amplitude of the oscillations exceeding 10 % of the total resistance in the case of the ring with a radius of 160 nm. Beside the h / e oscillations, we resolve the contributions from higher harmonics of the AB oscillations. The observation of a local resistance minimum at B = 0 T in both rings is a signature of the destructive interference of the holes’ spins. We show that this minimum is related to the minimum in the h / 2 e oscillations.

Mixing in Au/Si system by nuclear energy loss

Abstract: In the present work, we report the formation of silicide phases in the Au/Si system by ion beam mixing at room temperature. The samples (58 nm Au on Si) were irradiated by 1 MeV Xe ions. The ion energy was chosen in such a way that it deposits maximum energy at the interface. The Rutherford backscattering spectrometry measurements were done on the pristine and irradiated samples to determine the composition of mixed region. Grazing incidence X-ray diffraction measurements were performed which showed the formation of silicide phase (Au2Si, Au3Si, Au5Si and Au5Si2). Scanning electron microscopy measurements indicated the micron size crystallites in the irradiated samples.