Physics of superconducting nanowires. We have recently discovered that superconducting nanowires undergo pair-breaking quantum phase transition (QPT) driven by magnetic field.  Excellent agreement with the critical theory has been obtained and the microscopic nature of this transition is fully understood.  Somewhat surprising the behavior of one-dimensional superconductors in zero field is much less clear and present many unresolved problems. One of them is the mechanism of the suppression of the critical temperature in utra-thin nanowires. The others include the contribution of quantum phase slips in suppression of superconductivity, possible interaction between phase slips, and effect of dissipation. To answer these questions our group fabricates superconducting nanowires made of simple BCS superconductors and systematically studies their properties by measuring Tc , superconducting gap (by tunneling) and superfluid density (by kinetic inductance measurements).  We also plan to fabricate  nanowires with an "engineered" disorder, where suppression of the magnitude of the order parameter and loss of phase coherence occur at different values of a driven parameter. We are also developing a technique for fabrication of nanowires made of cuprate superconductors. 

Noise properties of organic devices. We have developed a cross-correlation current noise measurement technique, which allows to measure noise of organic light emitting diodes and solar cells with much higher sensitivity and in much wider frequency range compared to standard methods used by other groups. Using this method we have discovered the presence of shot noise in fairly thick organic devices. We anticipate that shot noise can be used to characterize non-uniform, filamentary transport in these devices. The project is carried out in collaboration with experimentalists who supply us with organic devices and with theorists who work on molecular-dynamic simulation of actual transport in organic materials. 

Noise in inorganic devices.  Low level of electrical and optical noise  is important for operation of semiconductor transistors, LEDs and detectors. Careful noise measurements carried out in a broad frequency and temperature ranges are capable to identify processes that limit device performance and provide information not accessible by simple I(V) and impedance measurements. We are interested in collaborative studies both with industrial and academic labs which involve noise characterization. Current projects include the study of Si hetero-junction solar cells and perovskite solar cells.     

Probing Non-local spin transport at high frequencies . The goal of this project it to determine time-scales of spin-current propagation in metallic and inorganic spin-valve devices.