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Theory of Exceptional Electronic Properties of Selected Transition Metal Compounds

English title Theory of Exceptional Electronic Properties of Selected Transition Metal Compounds
Applicant Rice T. Maurice
Number 131824
Funding scheme Project funding (Div. I-III)
Research institution Institut für Theoretische Physik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Theoretical Physics
Start/End 01.09.2011 - 31.08.2013
Approved amount 166'164.00
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Keywords (2)

High Temperature Superconductivity; Large Thermoelectric Seebeck Coefficients

Lay Summary (English)

Lead
Lay summary

       This project consists of two parts. The first is concerned with developing a microscopic theory, namely a theory that starts from electrons moving in the ionic potentials and interacting via their Coulomb repulsion, which explains the high temperature superconductivity and other highly anomalous electronic properties found in the cuprate compounds. The second project will focus on the microscopic theory of the giant thermoelectric power factor exhibited by a particular transition metal compound, FeSb2 , at low temperatures. The recent discovery of this effect opens up possibilities of novel cooling devices for high temperature superconductors and other applications.

       Although theoretical investigations of the very special electronic properties of the cuprate materials have been underway ever since their discovery by Drs. Alex Mueller and Georg Bednorz more than two decades ago, a comprehensive and consistent description of these properties is still lacking. Some five years ago, I together with two colleagues, put forward an ansatz, or phenomenological assumption, to describe the unique properties observed in the key underdoped pseudogap region of the phase diagram of the cuprates. This ansatz has had considerable success in explaining a wide variety of the mysterious properties that characterize this phase. The first project will concentrate on extending and refining this ansatz further, with special attention to describing both the origin of the superconductivity and its subtle interplay with antiferromagnetism and the unusual partially truncated Fermi surface. It will be based on insights recently obtained from simpler but related microscopic models. A better justification and understanding of the ansatz in terms of the underlying strongly interacting electron system will be sought. The long term goal is to gain a fundamental understanding of the very special and so far unique properties of the cuprate superconductors

   The very recent discovery of the unique thermoelectric properties of FeSb2 at low temperatures is a challenge to theory. This material belongs to the small group of iron compounds, which show a crossover from weakly paramagnetic behavior at low temperatures to strongly paramagnetic above room temperature. Earlier band structure calculations predicted that, in contrast to closely related FeSi, the groundstate here should be semimetallic not semiconducting. This difference is consistent with the increase in the thermoelectric power factor. However a full microscopic theory for these exceptional transport properties is lacking and will be the goal of this second project. Success will give us new insights into the origins of exceptional thermoelectric properties, which may have important technological consequences.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Different roles of Zn $\^{}$\{$2+$\}$ $ and Li $\^{}$\{$+$\}$ $ impurities in the CuO $ \_2 $ plane in undoped cuprate compounds
Mei Jia-Wei (2013), Different roles of Zn $\^{}$\{$2+$\}$ $ and Li $\^{}$\{$+$\}$ $ impurities in the CuO $ \_2 $ plane in undoped cuprate compounds, in arXiv preprint , 1301.5208.
Publisher's Note: Numerical study of charge transport of overdoped La\_ $\{$2- x$\}$ Sr\_ $\{$x$\}$ CuO\_ $\{$4$\}$ within semiclassical Boltzmann transport theory [Phys. Rev. B 87, 035129 (2013)]
Buhmann Jonathan M, Ossadnik Matthias, Rice TM, Sigrist Manfred (2013), Publisher's Note: Numerical study of charge transport of overdoped La\_ $\{$2- x$\}$ Sr\_ $\{$x$\}$ CuO\_ $\{$4$\}$ within semiclassical Boltzmann transport theory [Phys. Rev. B 87, 035129 (2013)], in Physical Review B, 87(11), 119904-119904.
Spin Density Wave Fluctuations and p-Wave Pairing in Sr\_ $\{$2$\}$ RuO\_ $\{$4$\}$
Huo Jia-Wei, Rice TM, Zhang Fu-Chun (2013), Spin Density Wave Fluctuations and p-Wave Pairing in Sr\_ $\{$2$\}$ RuO\_ $\{$4$\}$, in Physical review letters, 110(16), 167003-167003.
Spin States of dopant holes in HgBa $ \_2 $ CuO $ \_ $\{$4+$\backslash$ delta$\}$ $
Mei Jia-Wei, Soluyanov Alexey A, Rice TM (2013), Spin States of dopant holes in HgBa $ \_2 $ CuO $ \_ $\{$4+$\backslash$ delta$\}$ $, in arXiv preprint , 1309.2119.
Theory of superconductivity in a three-orbital model of Sr 2 RuO 4
Wang Q. H., Platt C., Yang Y., Honerkamp C., Zhang F. C., Hanke W., Rice T. M., Thomale R. (2013), Theory of superconductivity in a three-orbital model of Sr 2 RuO 4, in EPL (Europhysics Letters), 104(1), 17013-17013.
A phenomenological theory of the anomalous pseudogap phase in underdoped cuprates
Rice TM, Yang KY, Zhang FC (2012), A phenomenological theory of the anomalous pseudogap phase in underdoped cuprates, in REPORTS ON PROGRESS IN PHYSICS, 75(1), 016502-1-016502-36.
Enhanced Josephson tunneling between high-temperature superconductors through a normal pseudogap underdoped cuprate with a finite-energy cooperon
Huang K, Chen WQ, Rice TM, Zhang FC (2012), Enhanced Josephson tunneling between high-temperature superconductors through a normal pseudogap underdoped cuprate with a finite-energy cooperon, in EPL, 99(2), 24002-1-24002-5.
Interlayer couplings and the coexistence of antiferromagnetic and d-wave pairing order in multilayer cuprates
Chen WQ, Gan JY, Rice TM, Zhang FC (2012), Interlayer couplings and the coexistence of antiferromagnetic and d-wave pairing order in multilayer cuprates, in EPL, 98(5), 57005-1-57005-5.
Magnetic Response in the underdoped cuprates
James A.J.A., Konik R.M., Rice T.M. (2012), Magnetic Response in the underdoped cuprates, in Physical Review B, 86, 100508-1-100508-5.
Possible Fermi Liquid in the Lightly Doped Kitaev Spin Liquid
Mei JW (2012), Possible Fermi Liquid in the Lightly Doped Kitaev Spin Liquid, in PHYSICAL REVIEW LETTERS, 108(22), 227207-1-22707-4.
Microscopic model for the semiconductor-to-ferromagnetic-metal transition in FeSi1-xGex Alloys
Yang KY, Yamashita Y, Lauchli AM, Sigrist M, Rice TM (2011), Microscopic model for the semiconductor-to-ferromagnetic-metal transition in FeSi1-xGex Alloys, in EPL, 95(4), 47007-1-47007-5.

Abstract

This proposal consists of two projects. The first is concerned with the microscopic theory of the high temperature superconductivity and other highly anomalous electronic properties found in the cuprates. The second will focus on the microscopic theory of the giant thermoelectric power factor exhibited by FeSb2 at low temperatures. The recent discovery of this effect opens up the possibility of novel cooling devices for high temperature superconductors and other applications. Although theoretical investigations of the very special electronic properties of the cuprate materials have been underway ever since their discovery more than two decades ago, a comprehensive and consistent description is still lacking. Some four years ago, I together with two colleagues, put forward an ansatz to describe the unique properties observed in the key underdoped pseudogap region of the phase diagram. This ansatz has had considerable success in explaining a wide variety of the mysterious properties that characterize this phase. The first project will concentrate on extending and refining this ansatz further, with special attention to describing both the origin of the superconductivity and its subtle interplay with antiferromagnetism. It will be based on insights recently obtained from simpler but related microscopic models. A better justification and understanding of the ansatz in terms of the underlying strongly correlated electron system will be sought. The very recent discovery of the unique thermoelectric properties of FeSb2 at low temperatures is a challenge to theory. This material belongs to the small group of iron compounds, which show a crossover from weakly paramagnetic at low temperatures to strongly paramagnetic above room temperature. Earlier band structure calculations predicted that, in contrast to closely related FeSi, the groundstate here should be semimetallic not semiconducting. This difference is consistent with the increase in the thermoelectric power factor. However a full microscopic theory for these exceptional transport properties is lacking and will be the goal of this second project.
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