Events Archive

Condensed Matter Seminar, Christian Schoenenberger, "Cooper-Pair Splitting and Spectroscopy in Double Quantum Dot Devices with Superconducting Charge
Mon, Mar 10, 2014, 1:15 pm2:30 pm
An elegant idea for the creation of entangled electrons in a solid-state device is to split Cooper pairs, which are in a spin singlet state, by coupling a superconductor to two parallel quantum dots (QDs) in a Y-junction geometry [1]. Cooper pair splitting (CPS) was investigated recently in devices based on InAs nanowires [2,3] and carbon…
Special Condensed Matter Seminar, Dan Dessau, Electronic Interactions in Cuprate High-Temperature Superconductors – an ARPES study
Tue, Feb 25, 2014, 1:15 pm2:30 pm
Using high resolution ARPES we analyze the electronic scattering rates of cuprate superconductors as a function of temperature, energy, and doping. In the normal state we show the smooth and continual evolution from the heavily overdoped Fermi liquid limit to the optimally doped Marginal Fermi liquid limit and beyond, with these results showing…
SPECIAL Condensed Matter Seminar, Enam Chowdhury, "Understanding strong field laser solid interaction with few cycle femtosecond pulses"
Tue, Feb 18, 2014, 2:00 pm3:00 pm
As femtosecond laser interacts with matter in fundamentally different ways than how continuous wave (CW) or nano-second laser interacts, it gives rise to many interesting phenomena which may open doors for exciting future applications, like plasmon coupled high harmonic generation [Park 2011] nano-electronics [Chimmalgi 2005], etc. CW and nano…
Condensed Matter Seminar, Leonid Glazman, "Helical edge resistance introduced by charge puddles"
Mon, Feb 17, 2014, 1:15 pm2:30 pm
Electron puddles created by doping of a 2D topological insulator may violate the ideal helical edge conductance. Because of a long electron dwelling time, even a single puddle may lead to a significant inelastic backscattering. We find the resulting correction to the perfect edge conductance. Generalizing to multiple puddles, we assess the…
Condensed Matter Seminar, Dale Van Harlingen, “Transport and Josephson phenomena in hybrid superconductor-topological insulator devices”
Mon, Feb 10, 2014, 1:15 pm2:30 pm
We are studying the transport properties of hybrid S-TI-S devices fabricated by depositing superconductor electrodes onto topological insulators. In top-gated Nb-Bi2Se3-Nb junctions, we have measured the Josephson supercurrent and conductance as a function of geometry, temperature, and gate voltage in order to determine the nature of the charge…
Condensed Matter Seminar, Waseem Bakr, "Synthetic condensed matter systems with ultracold atoms"
Mon, Dec 9, 2013, 1:15 pm2:30 pm
Recent advances in preparing, probing and manipulating ultracold atomic gases enable studying condensed matter physics in a very controlled setting. In the first part of my talk, I will describe quantum gas microscopy, a powerful tool for imaging and manipulating strongly interacting quantum gases containing thousands of atoms at the single atom…
Condensed Matter Seminar, Victor Galitski, "Topological Kondo Insulator"
Mon, Nov 25, 2013, 1:15 pm2:30 pm
In this talk I will review recent theoretical work on a new class of topological material systems - topological Kondo insulators, which appear as a result of interplay between strong correlations and spin-orbit interactions. I will start with introducing the by now standard theory of topological band insulators and explain the Fu-Kane method to…
Special Condensed Matter Seminar, James Murray, "Superconductivity on the brink of spin-charge order in doped honeycomb bilayer"
Fri, Nov 22, 2013, 11:00 am12:00 pm
Using a controlled weak-coupling renormalization group approach, we establish the mechanism of unconventional superconductivity in the vicinity of spin or charge ordered excitonic states for the case of electrons on the Bernal stacked bilayer honeycomb lattice. With one electron per site this system exhibits nearly parabolically touching…
Condensed Matter Seminar, Hsin Lin, "Nontrivial spin texture of the coaxial Dirac cones on the surface of topological crystalline insulator SnTe"
Tue, Nov 5, 2013, 2:00 pm4:00 pm
The recently discovered topological crystalline insulators harbor Dirac surface states protected by a discrete set of crystalline space group symmetries and show immense promise for novel quantum applications. In this talk, I will present a first principles investigation as well as a model Hamiltonian of the nontrivial surface states and their…
Condensed Matter Seminar, Leonid Levitov , "Atomic collapse in graphene"
Mon, Nov 4, 2013, 1:15 pm2:30 pm
Since the discovery that electrons in graphene behave as massless Dirac fermions, the single-atom-thick material has become a fertile playground for testing exotic predictions of quantum electrodynamics, such as Klein tunneling and the fractional quantum Hall effect. Now add to that list atomic collapse, the spontaneous formation of electrons and…
Condensed Matter Seminar, Yigal Meir, "Kondo Physics in Quantum Point Contacts"
Mon, Sep 30, 2013, 1:15 pm2:30 pm
Quantum point contacts (QPCs) are the basic building blocks of any mesoscopic structure, and display quantized conductance, reflecting the quantization of the number of transparent channels. An additional feature, coined the "0.7 anomaly", has been observed in almost all QPCs, and has been a subject of intensive debate in the last couple of…
Condensed Matter Seminar, Hong Ding, Institute of Physics, Chinese Academy of Sciences, "Probing iron-based superconductivity by photoelectrons"
Mon, Sep 9, 2013, 1:15 pm2:30 pm
Angle-resolved photoemission spectroscopy (ARPES) has been used extensively in studying electronic structure and superconducting gap of the iron-based superconductors (IBSCs). In this talk, I will present our ARPES results on the IBSCs, mainly focus on high-resolution measurements of the superconducting gap of many different IBSCs. Our results…
Condensed Matter Seminar, Xi Dai, "Topological phases in mix valence compounds"
Fri, Aug 30, 2013, 2:00 pm4:00 pm
In this talk, I will propose that the mix valence phenomena in some of the rare earth compounds will naturally lead to non-trivial topology in band structure.One of the typical example is SmB6, where the intermediate valence of Sm generates band inversion at the X point and the non-trivial Z2 index. Other than SmB6, YbB6 and YbB12 are both…
Quantum Sciences Seminar Series - David DiVincenzo, RWTH Aachen - "Engineering the Solid State Quantum Computer"
Mon, Jul 15, 2013, 1:30 pm2:30 pm
Progress on solid state qubits, particularly Josephson junction devices, now brings us to the possibility of planning a scalable, multi-qubit architecture.  While we can envision how the quantum part of device can be designed to effectively implement fault tolerant error correction, I will argue that, if implemented with present-day techniques,…
Condensed Matter Seminar, Liang Fu, MIT, From Topological Crystalline Insulator to Anderson Transition
Mon, May 13, 2013, 1:15 pm2:30 pm
Structure and symmetry play important roles in determining electronic properties of periodic solids. The interplay between crystalline symmetry and electronic topology leads to new phases of matter dubbed topological crystalline insulators, which possess protected surface states with unique and tunable electronic properties. In this talk, I…
Condensed Matter LUNCH Seminar, Chen Fang, PU and Suyang Xu, PU
Wed, May 1, 2013, 12:00 pm1:00 pm
Chen Fang will discuss Crystalline Topological Insulators SuYang Xu will discuss Protected & Broken Symmetries in TIs

Special Condensed Matter Seminar, Kai Sun, U of Michigan at Ann Arbor, Kondo insulators: insulator, metal or topological insulator?
Tue, Apr 30, 2013, 3:30 pm5:00 pm
In the last few decades, various puzzles have emerged in the study of strongly-correlated materials. In a family of strongly-correlated insulators, known as Kondo insulators, one such long-standing puzzle has remained open for over 40 years. In particular, it has been found that some Kondo insulators display strange electrical transport that…
Condensed Matter Seminar - Jeremy Levy, University of Pittsburgh, Oxide Nanoelectronics On Demand
Mon, Apr 29, 2013, 1:15 pm2:30 pm
Electronic confinement at nanoscale dimensions remains a central means of science and technology. I will describe a novel method for producing electronic nanostructures at the interface between two normally insulating oxides, LaAlO3 and SrTiO3. These structures and devices are “written” by a conductive atomic force microscope probe in ambient…
Mon, Apr 22, 2013, 1:15 pmMon, Apr 15, 2013, 2:30 pm