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Congratulations to Prof. Zhang for becoming an elected fellow of the American Physical Society.

December 2014

 

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Anti-Feromagnetism and Surface reconstruction at the Surface of Ca(Fe1-xCox)2As2

February 2014

We have carried out LEED I-V analysis to identify the stripe-ordered phase observed at the surface of Ca(Fe1-xCox)2As2 (x=0 and 0.075). The surface consists of half-Ca layer with a (1×2) structure. These surface Ca atoms move inward ~0.5Å and the surface As-Fe2 -As layer is buckled. DFT calculations show that the (1×2) phase is stabilized by the bulk antiferromagnetic ordering through the spin-charge-lattice coupling, providing a signature of AMF ordering at the surface. Furthermore, STS measurements show the presence of a superconducting gap on the ordered (1×2) surface, while the spectra always have a finite zero-bias conductance. These observations result from a combination of the reconstructed surface, which tends to be both AFM ordered and superconducting due to the proximity to the superconducting bulk. The surface-stabilized coexistence of superconductivity and AFM ordering raises the prospect of growing artificial structured materials with this property.

Phys. Rev. Lett. 112, 077205 (2014).

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New PNAS Publication

December 2010/January 2011

Jing Teng, Chen Chen, Yimin Xiong, Jiandi Zhang, Rongying Jin and E. W. Plummer have recently reported in Proceedings of the National Academy of Sciences [PNAS 110, 898 (2013)] the observation of extremely large spin-charge-lattice coupling driven by the broken symmetry present at the surface. The study was conducted on single crystals grown at LSU of the newly discovered Fe-based superconductors Ba(Fe1-xCox)2As2, using high resolution inelastic electron scattering to proble the lattice dynamics. A paper titled: "Direct Determination of the Electron-Phonon Coupling Matrix Element in a Correlated System" has been published in PRL 105, 256402 (2010) . This work is done in collaboration with Jiandoing Guo’s group at the Institute of Physics, Chinese Academy of Sciences, and Dr. Plummer’s group. Gu’s group at BNL provided the high-temperature superconductor crystal.

 

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Our group welcomes a new graduate student

July 28, 2012

Lin Li, a PhD student at the Institute of Physics in Beijing, China joins our research group.

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APS March Meeting in Boston, MA

February 27-March 2, 2012. Boston, MA.

Congratulations to all our group members for another successful APS meeting.

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Congratulations to Dr. Zhaoliang Lao for succesfully defending the second part of his PhD Thesis at Louisiana State University.

October 26, 2012

Dr. Zhaoliang Lao, a dual degree student, has has completed his PhD research by defending the second part of is work at Louisiana State University.

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Congratulations to Dr. Zhaoliang Lao for succesfully defending his PhD thesis in China

November 17, 2011

Dr. Zhaoliang Lao, a dual degree student, has obtained his PhD from the Chinese Academy of Sciences in China. Cheers!

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New Visiting Professor

November 2011

Dr. Weishi Tan is a new visting professor from Nanjing University of Science and Technology.

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New Board of Regents Grant

September 2011

Dr. Jiandi Zhang Co-PI along with Prof. Rongying Jin (PI) have recieved a new grant from the Louisiana Board of Regents to acquire an X-ray diffractometer in order to perform crystallographic analysis of polycrystaline materials and thinl films.

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Congratulations to Dalgis Mesa on passing her General Examination

April 27, 2011

Dalgis Mesa has succesfully defended her thesis proposal. Congrats !

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Congratulations to Zhaoliang Lao on passing his General Examination

April 25, 2011

Zhaoliang Lao has succesfully defended his thesis proposal. Congrats !

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American Physical Society Meeting

March 21-25, 2011 in Dallas, TX

Congratualtions to our group members for another successful APS meeting!

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Laser MBE/STM/XPS/LEED system

December 2010

Our main experimental toy, the Laser MBE/STM/XPS/LEED system, has been upgraded such that now we will have capability of performing angle-resolved photoemission. A 2D CCD detector has been used to upgrade our PHOIBOS 150 electron analyzer for momentum resolved photoelectron spectroscopy.

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New PRL Publication

December 2010/January 2011

A paper titled: "Direct Determination of the Electron-Phonon Coupling Matrix Element in a Correlated System" has been published in PRL 105, 256402 (2010) . This work is done in collaboration with Jiandoing Guo’s group at the Institute of Physics, Chinese Academy of Sciences, and Dr. Plummer’s group. Gu’s group at BNL provided the high-temperature superconductor crystal.

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Congratulations to Yi Li on passing her General Examination

November 30, 2010

Yi Li has succesfully defended her thesis proposal. Congrats !

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ICAM Workshop

October 27-30, 2010

An ICAM workshop, titled as “Novel Emergent Phenomena Created by Special Confinement” and organized by our group, was held at LSU (Oct. 27-30, 2010). For more information please click on the ICAM link .

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New NSF Grant!

July 2010

A new NSF grant has been awarded to the group for the research on “Meta-to-Insulator Transition at Correlated Electron Interfaces: In-Situ Growth and Characterization of Thin Oxide Films.” Congratulations!

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New DOE Grant!

September 2009

A joint DOE grant for working on “Emergent Functionality in Transition-Metal Compounds Driven by Spatial Confinement” has been awarded to Prof. Plummer’s and our group. Congratulations!

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New PRL Publication

September 2009

A new paper titled: "Surface Geometric and Electronic Structures of BaFe2As2 (001)" has been published in Physical Review Letters [Phys. Rev. Lett. 103, 076104 (2009)] . This work is in collaboration with Plummer’s and Jin’s group at LSU and also Pan’s group in University of Houston as well colleagues in ORNL.

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Dual-Doctorate Degree Program

August 2009

Dean Kevin Carman, Prof. Ward Plummer, Prof. Rongying Jin and Prof. Jiandi Zhang (Physics & Astronomy) recently negotiated an agreement creating a unique dual-doctorate program between LSU’s Department of Physics & Astronomy and the Institute of Physics at Beijing’s Chinese Academy of Sciences. For more info see related web page: Dual-Doctorate Degree Program .

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Prof. Zhang has been highlighted in the cover of LSU webpage

June 2009

 

 

 

 

 

 

 

 

 

 

 

An article titled: “NSF Career Grant Series: LSU Professor Delves into Complex Materials with Novel Equipment” was highlighted in the cover on LSU webpage. For more info see related web page: Atomic Scale - Professor works with in situ vacuum .

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A new VT STM/AFM arrived

September 05, 2009

A new Omicron variable temperature scanning tunneling microscope with a Q-plus atomic force microscope has been integreted to our laser MBE/LEED/XPS system. It will be used for the characterization of the surface and thin films of transition metal compounds. Welcome, our new toy!

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New Gropup members !

August 26, 2009

Jing Teng, a new postdoctoral fellow, and Lina Chen, a new graduate student, have joined the group in the summer. WELCOME!

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New PNAS publication

August 25, 2009

A new paper titled "Anomalously Large Anisotropic Magnetoresistance in a Perovskite Manganite" has just been published in theProceedings of the National Academy of Sciences (PNAS), 106, 14224 (2009). This research is in collaboration between LSU, Ningbo Institute of Material Technology and Engineering and the Institute of Physics, Chinese Academy of Science, as well as the National Institute for Materials Science of Japan.

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NSF graduate research fellowship

May 15, 2009

Congratulations to Diane Alvarez for her prestigious NSF graduate research fellowship.

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Group Moving

December 20, 2008

Our group is going to join the Department of Physics and Astronomy at Louisiana State University starting at the begining of 2009. See details in Material Science Program.

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Scholarships awarded to our Graduate Students!

December 05, 2008

Congratulations to both Diane Alvarez and Yi Li! Diane is a receipient of the graduate scholarship from Alfred P. Sloan Foundation. Yi is awarded with the Economic Development Assistantship for pursuing her Ph. D. degree by Stephenson Enterpreneurship Institute at LSU.

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News from En Cai

December 2008

Congratulations to En Cai on recieving her Master's Degree in Physics from Florida International University. En Cai is now pursuing her Ph.D in UIUC. Anne, good luck!

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New PRL Publication

February 13, 2008

A new PRL publication titled "Manifestations of Broken Symmetry: The Surface Phases of Ca2-xSrxRuO4" has just been published. PRL 100, 066102 (2008)

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The new XPS/UPS setup grouped in our system

Fall 2007

 

 

Our high-resolution XPS/UPS system has nicely integrated into our UHV Laser-MBE/STM system, which is able to determine the chemical composition, bonding information and electronic properties of in-situ grown correlated elelectron materials

 

 

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A New SCIENCE Paper about Inherent Mott Metal-to-Insulator Transition

October 2007

Broadly speaking, a material can be classified as a metal if it contains itinerant electric charges ready for carrying electric current. The opposite is true in the case of insulators. In these, electric charges are localized and cannot move, so no electric conductivity exists. In a new class of so called correlated electron materials, such as high-temperature superconductors, electrons strongly interact and give rise to extraordinary phenomena including superconductivity. One such phenomenon is the Mott metal-insulator transition, originally discovered by Sir Nevill Mott, who won the 1977 Nobel Prize in Physics for his study of phase transitions from a metal to an insulator in certain materials, and for showing that these transitions are inherently driven by electron-electron interactions. Experimentally, Mott transitions can be produced but nearly always are accompanied by a structure transition, until now. In the October 26 issue of SCIENCE (volume 318, page 615), Prof. Jiandi Zhang of the Department of Physics, in collaboration with Prof. Plummer’s group at the University of Tennessee-Knoxville (UTK), R. Jin and D. Mandrus at Oak Ridge National Laboratory (ORNL), as well as his colleagues at the Institute of Physics in Beijing, China, demonstrates that a purely electronic Mott metal-to-insulator transition occurs at a crystalline surface of a transition-metal oxide. The broken translational symmetry at the surface creates this phase transition without participation of a crystal structural transformation. This finding offers a unique opportunity to gain insight into the nature of an inherent Mott transition, which is a key topic of study in condensed matter physics today.

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New funding for photoelectron spectroscopy setup

It is great news that our proposal on “Acquisition of an X-ray/UV photoelectron spectroscopy setup for materials research and education” has been funded by US department of Defense/Infrastructure Support Program. This new setup, which can provide us information of chemical composition and electronic properties, will be integrated with our current laser-MBE/STM for the studies of the surfaces and interfaces of oxide materials.

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A review article for the spin-waves in ferromegnetic metallic manganites

Doped manganese oxides (manganites) are of interest not only because they are a testing ground of the classicaldouble-exchange (DE) interaction mechanism for the observed “colossal” magnetoresistance (CMR), but alsobecause they exhibit an extraordinaryarena of emergent phenomena. Through the collaboration with colleagues at the University of Tennessee, ORNL, etc., we have systematically studied the unusual spin-waves behavior in ferromagnetic metallic manganites. The results are summarized in a recent invited review article to be appeared in J. of Physics: Conden. Matter.
Figure: Inelastic neutron scattering measured FM Magnon excitation energy of a prototype CMR single crystal (La0.7Ca0.7MnO3) plotted as a function of momentum qx  and qy in the momentum space (lower sheet) with a large Brillouin zone boundary (qx, qy = ± 0.5) deviation (indicated by the arrow)  from the expected values (upper sheet) from the simple DE Model.

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News from En Cai

En Cai got the first place in the Graduate Student Research Competition of Department of Physics, FIU.

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News from Dr. Hongwei Qu

Our former group member, Dr. Hongwei Qu has become an assistant professor in the Department of Electric and Computer Engineering, Oakland University. Congratulations to Hongwei and best wishes to him!

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Hao Sha has won two prizes!

Fall 2006

The 2006 Scholarly Forum, Research Paper and Oral Presentations Competition for Graduate Students, presented by the Graduate Students Association (GSA) at Florida International University and Second Prize in Chemistry and Physics Category Material Advantage Oral Technical Presentation, presented by Material Advantage Chapter at FIU.

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News from our former group member

Our former group member, Hongwei Qu, with his current group members at the University of Florida, recently successfully designed a tiny, easy-to-manufacture motion sensor, a development that could help popularize the sensors as standard equipment in personal electronics, medical devices and other applications. Fordetails,please go to http://www.sciencedaily.com/releases/2006/02/060210090229.htm.

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New PRL publications

Fall 2006

Two recent papers from our group collaborating with colleagues at Oak Ridge National Lab, etc. have been published in Physics Review Letters (PRL). "Evolution of Spin-Wave Excitations in Ferromagnetic Metallic Manganites", PRL .  96, 047204 (2006) and "Dopant-Induced Nanoscale Electronic Inhomogeneity in Ca2-xSrxRuO4", PRL 96, 066401 (2006) .

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2006 Americal Physical Society Meeting

January 20, 2006

Both Lei Cai and Hao Sha are going to give an oral presentation in the  coming March Meeting of American Physical Society at Baltimore, Maryland. Lei Cai will talk about his theoretical work on a nanoscale dipole flipping at the surface of a ferroelectric copolymer film. Hao Sha will talk about his recent study of magnetic inhomogeneities in manganites by using neutron scattering.

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Congratulations to Dr. Chenxi Lu!

September 1, 2005

After five years of hard work and determination, Chenxi Lu was awarded his Ph.D on August 2005. His theisis is titled: " The Correlation of Structure and Electronic Properties near the Surface of Transition Metal Oxides."

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NSF Career Award

February 1, 2004

Dr. Jiandi Zhang has just received a CAREER Award from the National Science Foundation. This award will provide fund for the study of New Phases at the Surface/Interfaces of Transition Metal Oxides.

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DOE Research Award

February 1, 2004

Our Materials Physics group has received another grant from the Department of Energy for the Research and Training of Using Neutron Scattering to Probe the Collective Phenomena in Doped Transition-Metal Oxides. More graduate students will be involved in the studies of complex materials with neutron!

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