Home Page of Professor
H. Dennis Drew's Group
Welcome
to the world
of magneto-optical
physics.
Research Interests
My current research interests encompass two areas
that are currently of great interest in condensed matter physics.
The first is in strongly correlated electron systems including the high
temperature superconductors. This field is currently considered one
of the most important problems in condensed matter physics because it has
been recognized that these materials may represent a breakdown of the standard
paradigm for the understanding of metals that has dominated materials science
for more than 50 years. Research in this area has dominated the efforts
of many of the elite condensed matter scientists for more than a decade.
In addition I have a research program in magnetic transition metal oxides
– the Colossal Magneto-Resistance (CMR) materials - which is another example
of strongly interacting electron systems. This research is part of
a collaborative MRSEC program supported by the NSF. It involves both
on campus and off campus researchers. The second major program is
research on the foundations of a computer technology based on quantum physics
– quantum computers and quantum communication. This is a large collaborative
effort involving several research groups on and off campus. My research
involves using optical techniques to probe semiconductor quantum dots as
candidates for the qubit of a quantum computer.
Main research interests of the group:
- High Temperature Superconductivity
- Colossal Magnetoresistance Materials
- Multiferroic Materials and their elementary excitations (electromagnons)
- Near Field Scanning Optical Microscopy
- Non-Fermi Liquid Physics
- Quantum Hall Effect
- Semiconductor Physics
Current Projects in bold.
People
- Graduate Students: Rolando
Valdes Aguilar
- Research Scientist: Don
Schmadel
- Research Associates: Andrei
Sushkov, Greg Jenkins.
- Former Members: Jeff Simpson, Lingyun Shi (†), John
Cerne, Ricardo Decca, Matt
Grayson, Andrea Markelz, Manuel
Quijada, Paul
Kolb, Ben Palmer, Laurent
Rigal, Geoff Evans and Young-Noh Yoon.
Publications (some links not updated):
- Electromagnons in multiferroic RMn2O5
compounds and their microscopic origin (Journal of Physics C. Special Issue
on Multiferroics (To be published)).
- Spin-phonon coupling in frustrated magnet CdCr2O4(PRB
2008)
- Colossal magnon-phonon coupling in multiferroic Eu0.75Y0.25MnO3 ( PRB 2007)
- Infrared Hall effect in the electron-doped high-Tc cuprate Pr2-xCexCuO4 ( PRB 2007)
- Infrared Hall conductivity of Na0.7CoO2 ( PRB 2007)
- Infrared Hall conductivity in optimally doped Bi2Sr2CaCu2O8+d: Drude behavior examined by experiment and fluctuation-exchange-model calculations(PRB 2007)
- Electromagnons in multiferroic YMn2O5 and TbMn2O5 (PRL 2007)
- Infrared Phonon signatures of multiferroicity in TbMn2O5 (PRB 2006)
- Infrared signature of ion displacement in the noncollinear spin state of orthorhombic YMnO3 (PRB 2006)
- Development of high-throughput, polarization-maintaining, near-field probes (Applied Optics 2006)
- Probing spin correlations with phonons in the Strongly Frustrated Magnet
ZnCr2O4 (PRL 2005)
- Optical imaging of multiphase coexistance in Nd1/2Sr1/2MnO3
(PRB 2004)
- Percolative effects in oxygen-depleted YBa2Cu3Ox
(PRB 2004)
- Infrared study of giant dielectric constant in Li- and Ti-doped NiO (PRB
2004)
- Magneto-optical Evidence for a Gapped Fermi Surface in Underdoped YBa2Cu3O6+x
(PRL 2004)
- Optical band-edge shift of anatase Ti1–xCoxO2–&delta
(PRB 2004)
- Measurement of the infrared magneto-optic properties of thin-film metals
and high temperature superconductors (Rev.
Sci. Inst. 2003)
- Temperature-dependent optical studies of Ti1–xCoxO2
(APL 2003)
- High temperature ferromangetism with a giant magnetic moment in transparent
Co-doped SnO2-&delta (PRL
2003)
- Exchange interaction effects on the optical properties of LuMnO3
(PRL 2003)
- Quasiparticles in high-temperature superconductors: Consistency of angle-resolved
photoemission and optical conductivity (PRB
2003)
- Ferromagnetism in laser deposited anatase Ti1–xCoxO2–&delta
(PRB 2003)
- Disentangling the Exchange Coupling of Entangled Donors in the Si Quantum
Computer Architecture (PRL 2003)
- Spectral Measurement of the Hall Angle Response in Normal State Cuprate
Superconductors (PRL 2002)
- Temperature dependence of low-lying electronic excitations of LaMnO3
(PRB 2001)
- Anomalous Proximity Effect in Underdoped YBa2Cu3O6+x
Josephson Junctions (PRL 2000)
- Indications of phase separation in polycrystalline La1–xSrxMnO3
for x~0.5 (PRB 2000)
- Infrared Hall Effect in High-Tc Superconductors: Evidence for Non-Fermi-Liquid
Hall Scattering (PRL 2000 pdf)
- Midinfrared Hall effect in thin-film metals: Probing the Fermi surface
anisotropy in Au and Cu (PRB 2000 pdf)
- Temperature-dependent scattering rate and optical mass in ferromagnetic metallic
manganites (PRB 1999 pdf
)
- Infrared Hall effect in YBCO: Temperature and frequency dependence
of Hall scattering (J. Low Temp. Phys. 1999 pdf
)
- Magnetoresistance of YBa_{2}Cu_{3}O_{7} in the cold spots model (PRB 1999
pdf )
- Optical conductivity of manganites: Crossover from Jahn-Teller small
polaron to coherent transport in the ferromagnetic state (PRB 1998 pdf
)
- Phenomenological interpretations of the ac Hall effect in the normal state
of YBa_{2}Cu_{3}O_{7} (PRB 1998 pdf
)
- Composite vortex model of the electrodynamics of type-II superconductors
(PRB 1997 pdf )
- Sum Rule for the Optical Hall Angle (PRL 1997 pdf
)
- Optical Evidence for the Dynamic Jahn-Teller Effect in Nd_{0.7}Sr_{0.3}MnO_{3}
(PRL 1996 pdf )
- Measurement of the Far-Infrared Magnetoconductivity Tensor of Superconducting
YBa_{2}Cu_{3}O_{7-d} Thin Films (PRL 1996 pdf
)
- Normal State ac Hall Effect in YBa_{2}Cu_{3}O_{7} Thin Films (PRL 1996 pdf
)
Preprints and Thesis:
- Greg Jenkins thesis (pdf 2004thesis)
- Infrared Hall effect in underdoped and optimally doped LSCO (CondMat
2005)
Past Events
UMD-MRSEC Workshop on Multiferroic Materials
Date: Friday November 17th 2006
Place: Kim Engineering Bldg. Rooms 1107 & 1111
Time: 9 am to ~ 8 pm
Schedule: Success
Recent Data:
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Last Updated on 08/16/2007
By R. Valdes Aguilar rvaldes@physics.umd.edu