Largest molecular spin found close to a quantum phase transition

February 26, 2018, Bielefeld University
Credit: CC0 Public Domain

An international research team headed by Professor Dr. Annie Powell, a chemist at the Karlsruhe Institute of Technology (KIT), and Professor Dr. Jürgen Schnack, a physicist at Bielefeld University, has synthesized a new magnetic molecule. The team has reported the largest ground state spin ever attained. It is publishing its new findings today (26.02.2018) in the new Nature partner journal npj Quantum Materials.

Every electron possesses a quantum mechanical intrinsic angular momentum, also called spin. The new magnetic molecule modelled at Bielefeld University and synthesized at the KIT reveals a spin in its ground state that is as large as that of 120 electrons combined. This makes it the largest spin ever observed in a single molecule. Magnetic are molecules containing magnetic ions such as iron or gadolinium. The researchers report the synthesis of Fe10Gd10. It has the geometric structure of a torus.

Scientists in the interdisciplinary research project found a so-called quantum phase transition that strongly influences the property of the molecule. In , substances change their behaviour fundamentally at quantum critical points. An example of a 'classical' phase transition is that of water boiling as it passes a certain temperature. Quantum phase transitions occur at a temperature of absolute zero. In the newly synthesized Fe10Gd10 molecule, 10,000 states are degenerate at the critical point. That means they have the same energy. On this absolutely flat energy surface, it is possible to switch between the individual states without using any energy. In such a situation, the thermodynamic quantity entropy adopts giant values. "It's as if you were standing on top of a high pointed mountain," explains Annie Powell. "A small change to the external parameters, for example, to the pressure, suffices for it to immediately drop steeply." Therefore, future research will examine how external pressure can be used to lead the molecule Fe10Gd10 beyond the .

Explore further: Researchers observe dynamical quantum phase transitions in an interacting many-body system

More information: Amer Baniodeh et al. High spin cycles: topping the spin record for a single molecule verging on quantum criticality, npj Quantum Materials (2018). DOI: 10.1038/s41535-018-0082-7

Related Stories

It's never too cold for quantum

August 1, 2017

The peculiar characteristics demonstrated by quantum critical points at absolute zero remain one of the great unsolved mysteries of science.

Stirring up a quantum spin-liquid with disorder

December 13, 2017

Disorder is generally thought to be detrimental to creating materials with unusual magnetism or other quantum phenomena. However, a team found that weak disorder surprisingly stabilizes a rare quantum state called a quantum ...

Monopole current offers way to control magnets

November 13, 2017

In work published in Physical Review Letters, scientists from RIKEN in Japan have discovered interesting new magnetic properties of a type of materials known as "quantum spin ice." These materials demonstrate interesting ...

Recommended for you

Pond dwellers called Euglena swim in polygons to avoid light

September 25, 2018

In any seemingly quiet pond the still waters actually teem with tiny pond dwellers called Euglena gracilis. Unseen to the naked eye, the single-celled organism spirals through the water, pulled along a relatively straight ...

A new way to count qubits

September 24, 2018

Researchers at Syracuse University, working with collaborators at the University of Wisconsin (UW)-Madison, have developed a new technique for measuring the state of quantum bits, or qubits, in a quantum computer.

Explainer: The US push to boost 'quantum computing'

September 24, 2018

A race by U.S. tech companies to build a new generation of powerful "quantum computers" could get a $1.3 billion boost from Congress, fueled in part by lawmakers' fear of growing competition from China.

0 comments

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.