Themes

Teams

The quantum theory lab of SPSMS pursues research in nanoelectronics, superconductivity, magnetism, and electronic correlations. We work in close collaboration with experimentalists.

Technique(s)

Highlights

31-03-2015
Legend: Q-constant energy scans (solid symbols), at two Bragg positions shown in the inset, fitted by a series of Gaussian functions (solid lines). This figure emphasizes one series of transverse modes when the scattering vector Q is parallel to the direction of the ordered antiferromagnetic ... More »
03-02-2015
Contact : Marc Sanquer
Nanowire transistors in the sub10 nm range are subject to process variability. A main cause is the surface roughness of the nanowire. A single dopant centered in the channel can also modify the room temperature electrical characteristics of the transistor.  Both the surface roughness and a ... More »
06-06-2014
Atomically clean superconducting graphene has been grown on thin rhenium films. This breakthrough paves the way to new hybrid superconducting nanostructures.   Graphene is not an intrinsic superconductor but can become superconducting by proximity effect when it is intimately connected ... More »
09-10-2013
Contact : Xavier Jehl
Electron pumps are devices delivering a quantized current when driven at a frequency f: I=Nef, where N is an integer and e the electron charge. Electron pumps capable of delivering a current higher than 100 pA (corresponding to f >600MHz) with sufficient accuracy are likely to become the direct ... More »
08-10-2013
Contact : Vladimir Mineev
Vladimir P. Mineev (INAC, CEA-Grenoble) and Grigory E. Volovik (Aalto University School of Science) are the 2014 Lars Onsager Prize Recipients. This prize from the American Physical Society recognizes outstanding research in theoretical statistical physics including the quantum fluids. It ... More »
01-10-2013
Contact : Christoph Groth
The software Kwant is ​​available to the scientific community at http://kwant-project.org. This new platform aims beyond the traditional goal of making simulations fast, i.e. efficient in terms of computer time.  Kwant allows researchers to study new quantum-physical ... More »
18-09-2013
Extreme conditions of high pressure, associated with low temperatures and high magnetic field are the corner stone for the exploration of  the phase diagrams of strongly correlated electron systems, and therefore for the discovery of new states of matter and of the interplay between the ... More »
11-03-2013
Contact : Bjorn Fåk
Measurements of elementary excitations of superfluid helium performed at INAC show the importance of process in three excitations processes in Bose condensates.   Liquid helium study is an extremely rich subject that can address many issues of quantum and statistical physics. 4He ... More »
02-10-2012
Contact : Eric Ressouche
The compound URu2Si2 is the object of intense investigations for twenty years because the nature of the phase transition observed at T0 = 17.5 K in this compound still remains a mystery despite an impressive experimental effort. Our polarized neutron diffraction measurements suggest that the ... More »
03-12-2011
Modeling strongly correlated systems is a very delicate task. For instance, the theory for the phonon spectrum of uranium has only been available since 2008. Our recent measurements have confirmed this theory and our results combined with new calculations provide an interpretation for the very ... More »
23-09-2011
This result is on the front page of Phys. Rev Lett. 107 (13). The article by S. Raymond et al., Understanding the Complex Phase Diagram of Uranium: The Role of Electron-Phonon Coupling, reports on an experimental study coupled to theoretical calculations explaining the phase diagram of uranium, for ... More »
01-07-2011
The june-august issue of C.R. Physique is devoted to Superconductivity of strongly correlated systems: three papers are written by SPSMS researchers, emphasizing the high level of international recognition on this topic obtained by the lab for years : Antiferromagnetism and superconductivity in ... More »
04-05-2011
Based on numerical simulations, we have reached a new step in our understanding of the mechanisms that drive the growth of carbon nanotubes.   One of the most commonly used methods for synthesizing carbon nanotubes is chemical vapor deposition (CVD). The reaction involves a liquid ... More »
05-04-2011
Contact: Xavier Jehl
We have designed and fabricated the first electron pump using silicon on insulator (SOI) in a standard microelectronics technology. These devices could be used as electrical current standards.   The definition of the ampere in the international system of units is based on the force ... More »
01-02-2011
Were you aware that atomic disorder in a metal could result in a quantum transition to an insulating state? Then, what about it when the metal is also a superconductor? Spatially resolved tunneling spectroscopy has revealed the spectral signature of this transition in this paradoxical ... More »
15-12-2010
We have just discovered a new spin ice, i.e., a magnetic system with a residual entropy at low temperature.   Statistical physics teaches us that a system’s entropy goes to a finite limit when the temperature approaches absolute zero. This is Nernst's principle, also called the ... More »
10-09-2010
Contact : Georgios Katsaros – SPSMS
When two superconductors are connected through a tunnel junction, electron pairs -- the so-called Cooper pairs -- can flow from one to the other. This phenomenon is known as the Josephson effect. We have produced a Josephson quantum dot device in which a single SiGe self-assembled quantum dot is ... More »
04-05-2010
Contact: Dai Aoki
It has been known for a couple of years that superconductivity in correlated electron systems can coexist with a ferromagnetic state. Our recent results surprisingly make evident that superconductivity can even be reinforced by a magnetic field, and that this behaviour seems to be generalized in ... More »
03-04-2010
In the quest for high critical temperature superconductors (HTCS), a new family of iron-based compounds was discovered in 2008, some of them containing arsenic while others, more recently found, contain selenium or tellurium. Our measurements, performed with a system of this latter type, show a ... More »
05-02-2010
Contact: Xavier Jehl
Following the downsizing of microelectronics devices, a large variability in the characteristics of nominally identical transistors is observed. These differences in their behaviour, which are awkward even at ambient temperature, are explained by electronic transport measurements performed at very ... More »
10-11-2009
One of the main characteristics of high critical temperature superconductors is the existence of an abnormally small density of electronic states at the Fermi level, in the normal state. We have just witnessed similar behaviour in a conventional, albeit very disordered, ... More »
10-10-2009
A neutron resonance spin echo (NRSE) option has recently been installed on the three-axis spectrometer IN22 (CRG at the ILL). This device enables a gain up to two orders of magnitude in terms of energy resolution, and permits precise measurements of dispersive excitation lifetimes.   The ... More »
01-06-2009
After more than 20 years of intense research, the nature of the phase which appears below 18 K in the compound URu2Si2 remains a mystery. Until now, no measurement using a microscopic probe has been able to directly link a physical parameter to this phase. We have just shown that this phase is ... More »
06-04-2009
Contact: Georgios Katsaros
Starting with a self-assembled SiGe island, we have fabricated a device in which we can precisely control the number of charge carriers. Thanks to the properties of the material in use, this device provides a means to manipulate the spin of the charge carriers in an unprecedented ... More »
03-02-2009
Contact : Massimo Mongillo
Using a single silicon nanowire, we have made the first prototype of a multipurpose device which can be used as a field effect transistor, a Schottky diode or a p-n diode. We obtain these functions using electrostatic gates to control the interfaces between the metallic source and drain contacts, ... More »
 

 

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