Professor Jarillo-Herrero awarded the DOE Early Career Award

Professor Jarillo-Herrero has been awarded the DOE Early Career Award for research in Quantum Transport in Topological Insulator Nanoelectronic Device.

DOE Office of Science Selects 65 Promising Researchers for Early Career Research Awards
Four from MIT receive DoE early career research grants

Congratulations to Javier for passing his Part III Exam!

Kudos to Javier for completing his third and final qualification exam at MIT!

Graphene on BN STM results published in Nature Materials

Graduate Student Javier Sanchez-Yamagishi and undergraduate Danny Bulmash’s work are featured in a newly published paper in Nature Materials. This work was done in colloboration with Brian Leroy at University of Arizona.

Scanning tunnelling microscopy and spectroscopy of ultra-flat graphene on hexagonal boron nitride

Graphene has demonstrated great promise for future electronics technology as well as fundamental physics applications because of its linear energy–momentum dispersion relations which cross at the Dirac point. However, accessing the physics of the low-density region at the Dirac point has been difficult because of disorder that leaves the graphene with local microscopic electron and hole puddles. Efforts have been made to reduce the disorder by suspending graphene, leading to fabrication challenges and delicate devices which make local spectroscopic measurements difficult. Recently, it has been shown that placing graphene on hexagonal boron nitride (hBN) yields improved device performance. Here we use scanning tunnelling microscopy to show that graphene conforms to hBN, as evidenced by the presence of Moiré patterns. However, contrary to predictions, this conformation does not lead to a sizeable band gap because of the misalignment of the lattices. Moreover, local spectroscopy measurements demonstrate that the electron–hole charge fluctuations are reduced by two orders of magnitude as compared with those on silicon oxide. This leads to charge fluctuations that are as small as in suspended graphene, opening up Dirac point physics to more diverse experiments.

Congratulations to Thiti, Valla and Qiong for passing their Qualification Exams!

Cheers go to our graduate students who just passed a round of quals seasons with flying colors:

-to Thiti for passing his Harvard Oral quals
-and to our first years Valla and Qiong for passing their MIT Part II General Exams.

another milestone on their road towards successful PhD careers!

Graphene & Jarillo-Herrero Lab featured on PBS Nova Special

The Jarillo-Herrero lab made its television debut last week on the NOVA special “Making Stuff Smaller”! Check out the episode online to see how graphene is made and hear from Pablo why graphene research is so exciting.
(graphene feature starts 18 mins in)

Hadar's Bi2Se3 paper accepted to Nano Letters!

Congratulations to Hadar for getting out our first TI paper for the group!

Surface State Transport and Ambipolar Electric Field Effect in Bi2Se3 Nanodevices
Hadar Steinberg, Dillon R. Gardner, Young S. Lee & Pablo Jarillo-Herrero
Nano Letters ASAP (2010)

Electronic transport experiments involving the topologically protected states found at the surface of Bi2Se3 and other topological insulators require fine control over carrier density, which is challenging with existing bulk-dopedmaterial. Here we report on electronic transport measurements on thin (<100 nm) Bi2Se3 devices and show that the density of the surface states can be modulated via the electric field effect by using a top-gate with a high-k dielectric insulator. The conductance dependence on geometry, gate voltage, and temperature all indicate that transport is governed by parallel surface and bulk contributions. Moreover, the conductance dependence on top-gate voltage is ambipolar, consistent with tuning between electrons and hole carriers at the surface.

Thiti's paper on dual-gated bilayer graphene accepted to PRL!

Preprint can be found at cond-mat

Electronic Transport in Dual-gated Bilayer Graphene at Large Displacement Fields

Thiti Taychatanapat, Pablo Jarillo-Herrero

We study the electronic transport properties of dual-gated bilayer graphene devices. We focus on the regime of low temperatures and high electric displacement fields, where we observe a clear exponential dependence of the resistance as a function of displacement field and density, accompanied by a strong non-linear behavior in the transport characteristics. The effective transport gap is typically two orders of magnitude smaller than the optical band gaps reported by infrared spectroscopy studies. Detailed temperature dependence measurements shed light on the different transport mechanisms in different temperature regimes.

Congratulations to Congrats to Qiong and Valla for passing part I

Congratulations to new group members Qiong Ma and Valla Fatemi for passing their first physics qualification exam at MIT!

Professor Jarillo-Herrero wins young scientist prize

Pablo Jarillo-Herrero, assistant professor of physics, is one of two winners of this year’s Young Scientist Prize in Semiconductor Physics, awarded by the International Union for Pure and Applied Physics. Read the press release here.

Professor Jarillo-Herrero awarded a 2009 David and Lucile Packard Fellowship

Professor Jarillo-Herrero  has won a 2009 David and Lucile Packard Fellowship, a five year, $875,000 grant.  Read the press release here.