DOI: 10.1209/epl/i2002-00347-0


Europhys. Lett., 60 (2) , pp. 276-280 (2002)

Quantum phase transition in the dioptase magnetic lattice

C. Gros¹, P. Lemmens², K.-Y. Choi³, G. Güntherodt³, M. Baenitz⁴ and H. H. Otto<sup>5

1</sup>  Fachbereich Physik, Postfach 151150, Universität des Saarlandes 66041 Saarbrücken, Germany
²  IMNF, TU Braunschweig, D-38106 Braunschweig, Germany
³  II. Physikalisches Institut, RWTH-Aachen Templergraben 55, 52056 Aachen, Germany
⁴  Max-Planck-Institut für Chemische Physik fester Stoffe MPI-CPfS, D-01187 Dresden, Germany
⁵  Institut für Mineralogie und Mineralische Rohstoffe, TU Clausthal D-38678 Clausthal-Zellerfeld, Germany

(Received 17 April 2002; accepted in final form 6 August 2002)

Abstract
The study of quantum phase transitions (see Sachdev S., Quantum Phase Transitions (Cambridge University Press, Cambridge) 1999), which are zero-temperature phase transitions between distinct states of matter, is of current interest in research since it allows for a description of low-temperature properties based on universal relations. Here we show that the crystal green dioptase , known to the ancient Romans as the gem of Venus, has a magnetic crystal structure, formed by the Cu(II) ions, which allows for a quantum phase transition between an antiferromagnetically ordered state and a quantum spin liquid.

PACS
71.20.Be - Transition metals and alloys.
73.43.Nq - Quantum phase transitions.
75.10.Jm - Quantized spin models.


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