CMSP Seminars @ICTP STASI RM Thursday 7 June from 11am - A.MOGHADDAM and H. KHANJANI

[CM Section]

Condensed Matter and Statistical Physics Seminars

Thursday 7 June
Luigi Stasi Seminar Room, first floor, Leonardo Building

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_
 From 11:00 to 11:45

_Title: Inducing Superconductivity in Two Dimensional Materials

Speaker: Ali Ghorban Zadeh Moghaddam (IASBS, Zanjan)

Abstract:
It is long believed that any ordered phase may not exist in two
dimensions (2D) due to the strong fluctuations. However recent
discoveries during last decades have changed this picture drastically.
A very intriguing question arises about the possibility of inducing
superconducting correlations in 2D. Beside fundamental interests,
it is proven that high temperature superconductivity also has two
dimensional physics and very recently a 2D superconductor at the
interfaces between certain insulators has been observed. Therefore
a suitable answer can shine light on the pass-way to the consistent
theory of high temperature superconductivity and heavy fermion interface
 superconductors. In this talk I first review the general properties of 2D
superconductors beside some historical introduction. Then I will focus
on our own contribution to the field consisting of proximity effect in
graphene and other 2D systems. In particular I will discuss over the
exotic proximity effect in MoS2 which we have found due to the interplay
of exchange field with intrinsic spin-orbit interaction.
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_From 11:45 to 12:15_

Title: Gauge-Field-Induced Anomalous Interference Effects in Graphene
SNS Junctions

Speaker: Hadi KHANJANI (IASBS, Zanjan)

Abstract:
It is well known that fictitious gauge fields are induced by strain and
elastic deformations in graphene. But the interference effects attributed
to these gauge fields remain almost unexplored. In this talk, I will
show how the supercurrent passing through the graphene-based
Josephson junctions can be influenced by the gauge fields. In particular
we find that the Josephson current is monotonically enhanced in the
presence of a constant pseudo-magnetic field induced by arc-shape
strain. On the other hand, when both magnetic and pseudo-magnetic
fields are present, Fraunhofer-like oscillations as function of the real
magnetic field flux are found. Intriguingly, the combination of two
kinds of gauge fields results in strong localization of the Josephson
current density and also appearance of large inflated vortex cores.
These findings reveal unexpected interference signatures of strain-
induced gauge fields in graphene SNS junctions mainly originated
from the time-reversal symmetric property of the pseudo-magnetic
fields and provide unique tools for sensitive probing of the pseudo-
magnetic fields.
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