Mr. Arthur Alexis Jules Lesage

MPhil student at the Cavendish Laboratory - Semiconductor Physics Group (academic year 2013-2014)
Intern at CEA Saclay - DSM/IRFU/SPhN - COMPASS collaboration (Summer 2013)
Undergraduate student at Supelec, French Grande Ecole specialising in electrical engineering (academic years 2011-2013)
French Licence of fundamental physics at the University of Paris Sud XI (academic year 2011)
French Preparatory school for Grandes Ecoles at Lycee Louis le Grand (academic years 2009-2011)

After having studied electrical engineering in France (where I come from) at Supelec, I did a 3 months internship at CEA Saclay in particle physics, within  the COMPASS collaboration (Summer 2014). I fitted the fragmentation functions of quarks into hadrons form parton distribution functions ad hadron multiplicities. I have had the opportunity to present my work during the collaboration analysis meeting in September 2014 at CERN.

Since October 2014, I have joined the Semiconductor Physics group for an MPhil to study the properties of 1D transport of electrons. In this work, I particularly focus on split-gates to create 1D channels for the electrons.

I am currently working on characterising the 0.7 anomaly in 1D conductance on AlGaAs/GaAs heterostructure. Indeed, the conductance G of 1D transport channels (split-gate in this case) is quantised and shows plateaux at integer multiples of Gº = 2×e²/h as it is plotted against the gate voltage Vg. However, an additional shoulder can be seen near the pinch-off voltage at G = 0.7×Gº. This is called the 0.7 anomaly and is not yet fully understood.

In this study, I will concentrate on the dependence of the 0.7 anomaly upon the dimensions of the split-gates. For this purpose, the multiplexer, which allows to measure more than 100 split-gates in a single cool down, will be used. This technique allows to only focus on the dimension dependencies of the phenomena, avoiding changing temperature. This work should be submitted by the end of August 2014 for my MPhil thesis. I should thus graduate from my MPhil in October 2014.