Unraveling the origin of the pseudogap in a charge density wave compound -- ScienceDaily

Unraveling the origin of the pseudogap in a charge density wave compound -- ScienceDaily

By combining a variety of different experimental techniques and theory, a group led by researchers at the U.S. Department of Energy's Argonne National Laboratory obtained unique insights into the nature of the pseudogap state in a canonical charge density wave material.

Ordinarily, atoms in a metal form a lattice. Under certain circumstances, the electrons in some of those atoms can crowd more densely in some areas, forming a so-called a charge density wave. The researchers found that niobium diselenide displays short-range charge density wave order and pseudogap behavior across large ranges of temperatures and doping.

"This has a profound influence on the properties of the material," said Stephan Rosenkranz, an Argonne physicist, in the Materials Science Division, who co-led the study.

The presence of charge density waves has also been associated with phenomena in materials that can superconduct, or conduct electricity perfectly without any loss at extremely low temperatures, and that display colossal magnetoresistance, changing electrical resistance in the presence of a magnetic field--both properties that makes them very useful in electronics and technologies. Because the physics of these behaviors likely affect how those very useful materials work, scientists are interested in understanding them more fully.

The scientists studied the phenomenon in a simple compound called niobium diselenide, which displays charge density wave order near the temperature at which superconductors work (about minus 280 degrees Fahrenheit). Under normal conditions, the charge density wave appears as long, uniform rows.

But when the researchers increased the temperature or mixed in atoms of other materials--a technique called doping--the charge density waves became less ordered. The previously long, uniform waves broke up into small pockets of locally well-ordered charge density waves, with random phases between waves in different pockets. This effect wasn't previously visible in other studies because that research looked at the average ordering across the material, which canceled out the phase variation.

Upon increasing temperature or doping, the material also lost the previously present coherent electronic excitations and displayed an energy gap across a large range of temperatures despite not having long-range ordering. This is similar to the behavior in the mysterious "pseudogap" state observed in high-temperature superconductors.

Understanding the physical properties underlying these phenomena in a relatively uncomplicated system, such as niobium diselenide, "helps us shed light on phenomena observed in more complex materials," Rosenkranz said.

The researchers measured the effects using scanning tunneling microscopy and angle-resolved photoemission, as well as X-ray scattering at the Advanced Photon Source, a DOE Office of Science user facility located at Argonne, using beamlines 11-ID-D and 6-ID-D.

Welcome to SUV System Ltd!

SUV System Ltd is ISO 90012008 Certified electronics distributor with 10 years of experiences.

We have built up long term business relationship with about many companies which are stockers and authorized agents. we have a steady and reliable supply to meet customer's demands to the greatest extent .Confidently, we are able to lower your cost and support your business with our years of professional service.

SUV System Ltd is Electronic Components Distributor Supplies,Find Quality Electronic Components Supplies Products IC(Integrated Circuits),Connectors,Capacitor,Resistors,Diodes,Transistors,LED at Suvsystem.com. Sourcing Other Energy, Environment, Excess Inventory Products from Manufacturers and Suppliers at Suvsystem.com

Electronic Components distributor:http://www.suvsystem.com

Connectors Distributor:http://www.suvsystem.com/l/Connectors-1.html

IC Distributor:http://www.suvsystem.com/l/IC(Integrated-Circuits)-1.html

LED Distributor:http://www.suvsystem.com/l/LED-1.html

Capacitor Distributor:http://www.suvsystem.com/l/Capacitor-1.html

Transistor Distributor:http://www.suvsystem.com/l/Transistors-1.html

Resistor Distributor:http://www.suvsystem.com/l/Resistors-1.html

Diode Distributor:http://www.suvsystem.com/l/Diodes-1.html

SUV System Ltd insists on the managing faith ofsincereness,speciality,foresight, win-win,so we build up stable-relationship customers located all over the world, including the States, Europe, Argentina, UAE, Malaysia, Australia,and India etc

we are focus on the following fields,and hope we can help you.

AVX Resistors Resistors TOSHIBA Diodes Switching Diodes ROHM Resistors Vishay resistors NXP Transistors Ligitek LED Chip Inductors ELPIDA IC High Precision Resistors Diodes Inc Texas Instruments(TI) IC Microchip IC Renesas parts IC MURATA IC NXP Diodes Resistor Arrays Fast Recovery Diodes MAXIM IC Bipolar Transistors NEC Transistors TOSHIBA Transistors Transistors Thin Film Resistors Chip Fuses AD IC INTERSIL IC ALTERA IC components Electronic News Zener Diodes FAIRCHILD diodes Freescale Semiconductor TI IC Cypress IC YAGEO Resistors Kingbrigt LED LED part Military IC
http://www.suvsystem.com/a/43496.aspx