RUcore: Rutgers University Community Repository
Interaction effects in high-mobility Si MOSFETs at ultra-low temperatures
Descriptive
TypeOfResource
Text
TitleInfo
(ID = T-1)
Title
Interaction effects in high-mobility Si MOSFETs at ultra-low temperatures
SubTitle
PartName
PartNumber
NonSort
Identifier
(displayLabel = );
(invalid = )
ETD_1276
Identifier
(type = hdl)
http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.000051966
Language
(objectPart = )
LanguageTerm
(authority = ISO639-2);
(type = code)
eng
Genre
(authority = marcgt)
theses
Subject
(ID = SBJ-1);
(authority = RUETD)
Topic
Physics and Astronomy
Subject
(ID = SBJ-2);
(authority = ETD-LCSH)
Topic
Metal oxide semiconductor field-effect transistors
Abstract
This dissertation focuses on the experimental study of the anomalous "metallic" behavior of the conductivity observed in high-mobility two-dimensional (2D) electron systems at low carrier densities (n) and temperatures (T). This intriguing phenomenon seems to defy one of the paradigms of our understanding of electron transport in 2D, the scaling theory of localization that claims that all electron states in 2D are localized. Our experimental object is the high-mobility silicon metal-insulator-oxide field effect transistor (Si MOSFET) in which this anomalous behavior is the most pronounced in comparison with other high-mobility devices.
We have explored in details the conductivity sigma in high-mobility Si MOSFETs over wide ranges of electron densities n=(2-3)x10^11 cm^-2 , temperatures T=30mK-4K, and magnetic fields B=0-5T. The low-temperature behavior of sigma in these systems is shaped by the interaction effects, which are amplified by the valley degeneracy and the interaction-driven renormalization of electron parameters. While exploring the temperature and magnetic field dependences of sigma far from the strongly localized regime ((sigma>>e^2/h) we observed for the first time the crossover between the “metallic” and “insulating” regimes with lowering temperature below ~0.3 K. We have attributed this crossover to the modification of the interaction correction to sigma at low T caused by a non-zero valley splitting and inter-valley scattering. All relevant quantities have been measured in independent experiments. In particular, the intervalley scattering rate tau_v^-1 has been extracted from the analysis of weak localization magnetoresistance. We found that the intervalley scattering rate is temperature-independent and the ratio tau_v/tau increases monotonically with decreasing the electron density ( au is the momentum relaxation time). These observations suggest that the roughness of the Si-SiO2 interface plays the major role in intervalley scattering. The detailed analysis of the sigma(T,B_||) data conducted with no adjustable parameters shows that the theory of interaction corrections to the conductivity of disordered systems adequately describes the experimental data at intermediate temperatures. At the same time, our data indicate that for better agreement with the experiment at low temperatures, the theory should take into account inter-valley scattering that strongly affect the interaction corrections in multi-valley systems.
We have explored in details the conductivity sigma in high-mobility Si MOSFETs over wide ranges of electron densities n=(2-3)x10^11 cm^-2 , temperatures T=30mK-4K, and magnetic fields B=0-5T. The low-temperature behavior of sigma in these systems is shaped by the interaction effects, which are amplified by the valley degeneracy and the interaction-driven renormalization of electron parameters. While exploring the temperature and magnetic field dependences of sigma far from the strongly localized regime ((sigma>>e^2/h) we observed for the first time the crossover between the “metallic” and “insulating” regimes with lowering temperature below ~0.3 K. We have attributed this crossover to the modification of the interaction correction to sigma at low T caused by a non-zero valley splitting and inter-valley scattering. All relevant quantities have been measured in independent experiments. In particular, the intervalley scattering rate tau_v^-1 has been extracted from the analysis of weak localization magnetoresistance. We found that the intervalley scattering rate is temperature-independent and the ratio tau_v/tau increases monotonically with decreasing the electron density ( au is the momentum relaxation time). These observations suggest that the roughness of the Si-SiO2 interface plays the major role in intervalley scattering. The detailed analysis of the sigma(T,B_||) data conducted with no adjustable parameters shows that the theory of interaction corrections to the conductivity of disordered systems adequately describes the experimental data at intermediate temperatures. At the same time, our data indicate that for better agreement with the experiment at low temperatures, the theory should take into account inter-valley scattering that strongly affect the interaction corrections in multi-valley systems.
PhysicalDescription
Form
(authority = gmd)
electronic resource
Extent
xv, 177 p. : ill.
InternetMediaType
application/pdf
InternetMediaType
text/xml
Note
(type = degree)
Ph.D.
Note
(type = bibliography)
Includes bibliographical references (p. 168-176)
Note
(type = statement of responsibility)
by Nikolai N. Klimov
Name
(ID = NAME-1);
(type = personal)
NamePart
(type = family)
Klimov
NamePart
(type = given)
Nikolai
Role
RoleTerm
(authority = RULIB);
(type = )
author
DisplayForm
Nikolai Klimov
Name
(ID = NAME-2);
(type = personal)
NamePart
(type = family)
Gershenson
NamePart
(type = given)
Michael
Role
RoleTerm
(authority = RULIB);
(type = )
chair
Affiliation
Advisory Committee
DisplayForm
Michael E Gershenson
Name
(ID = NAME-3);
(type = personal)
NamePart
(type = family)
Ransome
NamePart
(type = given)
Ronald
Role
RoleTerm
(authority = RULIB);
(type = )
internal member
Affiliation
Advisory Committee
DisplayForm
Ronald Ransome
Name
(ID = NAME-4);
(type = personal)
NamePart
(type = family)
Changra
NamePart
(type = given)
Premala
Role
RoleTerm
(authority = RULIB);
(type = )
internal member
Affiliation
Advisory Committee
DisplayForm
Premala Changra
Name
(ID = NAME-5);
(type = personal)
NamePart
(type = family)
Andrei
NamePart
(type = given)
Natan
Role
RoleTerm
(authority = RULIB);
(type = )
internal member
Affiliation
Advisory Committee
DisplayForm
Natan Andrei
Name
(ID = NAME-6);
(type = personal)
NamePart
(type = family)
Vitkalov
NamePart
(type = given)
Sergey
Role
RoleTerm
(authority = RULIB);
(type = )
outside member
Affiliation
Advisory Committee
DisplayForm
Sergey Vitkalov
Name
(ID = NAME-1);
(type = corporate)
NamePart
Rutgers University
Role
RoleTerm
(authority = RULIB);
(type = )
degree grantor
Name
(ID = NAME-2);
(type = corporate)
NamePart
Graduate School - New Brunswick
Role
RoleTerm
(authority = RULIB);
(type = )
school
OriginInfo
DateCreated
(point = );
(qualifier = exact)
2008
DateOther
(qualifier = exact);
(type = degree)
2008-10
Place
PlaceTerm
(type = code)
xx
RelatedItem
(type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier
(type = RULIB)
ETD
RelatedItem
(type = host)
TitleInfo
Title
Graduate School - New Brunswick Electronic Theses and Dissertations
Identifier
(type = local)
rucore19991600001
Location
PhysicalLocation
(authority = marcorg);
(displayLabel = Rutgers, The State University of New Jersey)
NjNbRU
Identifier
(type = doi)
doi:10.7282/T3H70FZ3
Genre
(authority = ExL-Esploro)
ETD doctoral
Back to the top
Rights
RightsDeclaration
(AUTHORITY = GS);
(ID = rulibRdec0006)
The author owns the copyright to this work
Copyright
Status
Copyright protected
Notice
Note
Availability
Status
Open
Reason
Permission or license
Note
RightsHolder
(ID = PRH-1);
(type = personal)
Name
FamilyName
Klimov
GivenName
Nikolai
Role
Copyright holder
RightsEvent
(ID = RE-1);
(AUTHORITY = rulib)
Type
Permission or license
Label
Place
DateTime
Detail
AssociatedEntity
(ID = AE-1);
(AUTHORITY = rulib)
Role
Copyright holder
Name
Nikolai Klimov
Affiliation
Rutgers University. Graduate School - New Brunswick
AssociatedObject
(ID = AO-1);
(AUTHORITY = rulib)
Type
License
Name
Author Agreement License
Detail
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.
Back to the top
Technical
ContentModel
ETD
MimeType
(TYPE = file)
application/pdf
MimeType
(TYPE = container)
application/x-tar
FileSize
(UNIT = bytes)
8704000
Checksum
(METHOD = SHA1)
9f9690ce18a5dc73ce3ead52872495a825a7b0ee
Back to the top
Statistical Profile