Under pressure: Germanium

April 6, 2011
Under pressure: Germanium
This image shows nanocrystalline germanium with hydrogen serving as pressure medium.

(PhysOrg.com) -- Although its name may make many people think of flowers, the element germanium is part of a frequently studied group of elements, called IVa, which could have applications for next-generation computer architecture as well as implications for fundamental condensed matter physics.

New research conducted by Xiao-Jia Chen, Viktor Struzhkin, and Ho-Kwang (Dave) Mao from Geophysical Laboratory at Carnegie Institution for Science, along with collaborators from China, reveals details of the element's transitions under . Their results show extraordinary agreement with the predictions of modern condensed matter theory.

(atomic number 32) is used in fiber-optic systems, specialized camera and microscope lenses, circuitry, and . Under ambient conditions it is brittle and semiconducting. But under pressure, the element should exhibit superconductivity, meaning that there is no resistance to the flow of an electric current.

The team's research, published in , discovered that under pressure of 66 GPa (about 650,000 atmospheres), germanium undergoes a structural change from one type of solid material to another that is metallic—meaning it conducts electricity. It then undergoes another structural change under pressure of 90 GPa (about 890,000 atmospheres). These findings matched theoretical predictions about the element's behavior under extreme pressure.

"A series of phase transitions was observed on compression of germanium that creates structures with increased density," Chen said. "We found extraordinary agreement between theory and experiment for the structures, energies, and compressional behavior. Though some of this behavior had been noted earlier, the agreement between the new highly accurate experimental results and theory really was quite remarkable."

The team's results show that superconductivity in this simple element is caused by phonons, or collective vibrations in the crystal structures that germanium assumes under pressure.

Explore further: Quantum mechanics predicts unusual lattice dynamics of vanadium metal under high pressure

Related Stories

Squashing Silane into Metal

January 9, 2009

(PhysOrg.com) -- Squeeze it hard enough and hydrogen, the most abundant and lightest element in our Universe, strangely takes on a metallic nature. During this state, as it loses hold of its electrons, hydrogen is believed ...

Superconducting hydrogen?

January 25, 2010

Physicists have long wondered whether hydrogen, the most abundant element in the universe, could be transformed into a metal and possibly even a superconductor -- the elusive state in which electrons can flow without resistance. ...

Roller coaster superconductivity discovered

August 18, 2010

Superconductors are more than 150 times more efficient at carrying electricity than copper wires. However, to attain the superconducting state, these materials have to be cooled below an extremely low, so-called transition ...

Resolving the high pressure phases of calcium

December 15, 2010

(PhysOrg.com) -- Significant experimental and theoretical work has been devoted to the electronic, structural and superconducting properties of calcium (Ca) at high pressure.

How do you make lithium melt in the cold?

January 10, 2011

Sophisticated tools allow scientists to subject the basic elements of matter to conditions drastic enough to modify their behavior. By doing this, they can expand our understanding of matter. A research team including three ...

Recommended for you

Professor solves 140-year fluid mechanics enigma

October 7, 2015

A Purdue University researcher has solved a 140-year-old enigma in fluid mechanics: Why does a simple formula describe the seemingly complex physics for the behavior of elliptical particles moving through fluid?

Perfectly accurate clocks turn out to be impossible

October 7, 2015

Can the passage of time be measured precisely, always and everywhere? The answer will upset many watchmakers. A team of physicists from the universities of Warsaw and Nottingham have just shown that when we are dealing with ...

The topolariton, a new half-matter, half-light particle

October 7, 2015

A new type of "quasiparticle" theorized by Caltech's Gil Refael, a professor of theoretical physics and condensed matter theory, could help improve the efficiency of a wide range of photonic devices—technologies, such as ...

Fusion reactors 'economically viable' say experts

October 2, 2015

Fusion reactors could become an economically viable means of generating electricity within a few decades, and policy makers should start planning to build them as a replacement for conventional nuclear power stations, according ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.