Neutral modes of the fractional quantum Hall effect have been shown to exchange energy with their fractionally charged counterparts, but it remains unknown whether they do so with the nearby integer quantum Hall edge channels. Researchers of the Nanolectronics group of SPEC, in collaboration with teams of the C2N (Palaiseau, France) and NIMS (Tsukuba, Japan) have performed a heat transport experiment in graphene answering this question.

Under a high magnetic field and at low temperatures, electrons in graphene can end up with all their spins perfectly aligned. The elementary excitations of such an ideal magnet, called spin waves or magnons, are intrinsically magnetic objects that nonetheless have an electrostatic nature, as they carry an electric dipole.

Researchers from the Nanoelectronics and the Modeling and Theory groups of SPEC, in collaboration with experimentalists from NTT-BRL and NIMS (Japan) and theorists from KAIST (Korea) have developed new, fully tunable electronic beam splitters in graphene, that directly rely on the crystalline symmetries of graphene.

Researchers from SPEC (in collaboration with the C2N and the University of Genoa) have observed the fading and partial reappearance of an electron injected at a finite energy into chiral one dimensional electronic channels propagating along the edges of a two dimensional electron system. These results will help elucidating to which extent these electrons can be used to implement the electronic analogues of quantum information experiments done with photons.

La métrologie (spectroscopie, mesures de temps ou de distances) ou encore la réalisation de réseaux optiques quantiques nécessitent des sources de photons uniques efficaces. Une équipe du SPEC à Saclay, en collaboration avec l'IQST d'Ulm en Allemagne, propose une voie originale pour obtenir une source de photons microondes uniques, simple, efficace et brillante.

The electron is an elementary particle carrying the elementary charge "e" that is a fundamental constant of physics. However, in a 2-dimensional confined conductor within an intense magnetic field (~ 10 T), the electrons can be organized into a new topologically correlated quantum state so that the electric current can be transported by fractional charges: e / 3, e / 4, e / 5 ....

( French version) Contact: Dr. Fabien PORTIER A conductor in equilibrium under a bias voltage shows current fluctuations proportional to its resistance and temperature. This type of noise is known as the Johnson-Nyquist noise, or equivalently, the thermal noise. In a quantum conductor, current fluctuations generate microwave photons which obey chaotic statistics (cf., blackbody radiation) if the conductor is at equilibrium.

If it truly does exist, a "supersolid" would represent a new state of matter that combines mechanical rigidity and superfluid properties. This would be a new phase of condensed matter, but whether such a state has indeed been discovered and how it can be reached is still far from clear. As reported in Physical Review B 80 (2009) 140504(R), researchers at SPEC have measured the low frequency elastic properties of solid helium-4 using ultra-sensitive acoustic techniques.

( Version française) We thought we knew transistor physics fairly well and in particular the millions of MOSFETs (Metal Oxyde Semi-conducteur Field Effect Transistor) which can be found at the core of our computers. However, as early as 1994, a new generation of very high mobility MOSFETs lead to experiments where one could study the regime of extremely low density (Kravchenko et al 1994).

A mixed team from ENS / CNRS / CEA-Saclay (SPEC) of the Pierre Aigrain Laboratory has for the first time highlighted the remarkable behavior of an electronic circuit when its miniaturization is extreme. These results are published in the journal Science. Researchers have shown that the basic laws of electricity, established since 1845, can no longer describe the properties of an electronic circuit when its dimensions reach the nanometer scale.