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SUMMARY:An effective theory for Heisenberg antiferromagnet on one-dimensio
nal frustrated lattices at high magnetic fields
DTSTART;VALUE=DATE-TIME:20181205T090500Z
DTEND;VALUE=DATE-TIME:20181205T092500Z
DTSTAMP;VALUE=DATE-TIME:20230330T011840Z
UID:indico-contribution-7@indico.bitp.kiev.ua
DESCRIPTION:Speakers: Olesia Krupnitska (Institute for Condensed Matter Ph
ysics\, NAS of Ukraine)\nWe consider the spin-1/2 antiferromagnetic Heisen
berg model on one-dimen-sional frustrated lattices (double tetrahedra chai
n [1]\, deformed octahedral chain [2]) placed in an external magnetic fiel
d with almost dispersionless (almost flat) lowest magnon band. The main go
al of our study is to develop a systematic theory for the low-temperature
high-field properties of these models\, using the localized magnons approa
ch [3\,4]. We construct an effective description of one-dimensional chains
with triangular and quadrangular traps by means of the localized magnons
concept within the strong coupling approximation. The obtained effective m
odels are much simpler than the initial ones: firstly\, the effective mode
ls have smaller number of sites and secondly\, and most importantly\, they
are unfrustrated. As a result\, one can apply well elaborated methods of
the quantum spin systems theory to discuss the properties of the initial
frustrated quantum antiferromagnets at high fields and low temperatures. W
e perform extensive exact diagonalization calculations to check the validi
ty of the obtained effective Hamiltonians by comparison with the initial m
odels.\n\n[1] M. Maksymenko\, O. Derzhko and J. Richter\, Acta Physica Pol
onica A **119**\, 860 (2011)\; Eur. Phys. J. B **84**\, 397 (2011).\n[2] J
. Strečka et al.\, Phys. Rev. B **95**\, 224415 (2017)\; Physica B **536*
*\, 364 (2018).\n[3] J. Schulenburg et al.\, Phys. Rev. Lett. **88**\, 167
207 (2002).\n[4] O. Derzhko\, J. Richter\, and M. Maksymenko\, Int. J. Mod
. Phys. B **29**\, 1530007\n(2015).\n\nhttps://indico.bitp.kiev.ua/event/2
/contributions/7/
LOCATION:
URL:https://indico.bitp.kiev.ua/event/2/contributions/7/
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