NMU Physics: Associate Professor

Rick (P. W.) Mengyan, Ph.D.
Associate Professor of PhysicsOffice Phone: (906) 227-2183
Email: pmengyan 'at' nmu_dot_edu
Office: 2513 Science Building
Ph.D. Physics, Texas Tech University (2014)
M.Sc. Physics, Texas Tech University
B.Sc. Physics, Northern Michigan University
B.Sc. Mathematics, Northern Michigan University
Psychology, Northern Michigan University
Teaching Links
Upcoming
Current
Winter 2022: Calculus-based Physics I: Lecture (PH 220-01: MTRF 11:00 to 11:50, 10238)
Winter 2022: Thermodynamics and Statistical Physics (PH 360-01: MWF 10:00 to 11:00, 11127)
Ongoing: Solid State Physics Research (email / come talk with me for details)
Past
Fall 2021: Algebra-based Physics I: Lecture (PH 201-01: MWRF 14:00 to 14:50, 80331)
Fall 2021: Calculus-based Physics II: Lecture (PH 221-01: MTRF 11:00 to 11:50, 80339)
Winter 2021: Calculus-based Physics I: Lecture (PH 220-01: MWRF 11:00 to 11:50, 10248)
Winter 2021: Calculus-based Physics I: Lab (PH 220-03: W 16:00 to 17:50, 10497)
Fall 2020: Algebra-based Physics I: Lecture (PH 201-01: MWRF 14:00 to 14:50, 80343)
Fall 2020: Calculus-based Physics II: Lecture (PH 221-01: MTRF 11:00 to 11:50, 80351)
Fall 2020: Calculus-based Physics II: Lab (PH 220 {-02: W 10:00 - 13:00, 80352; -03: W 16:00 to
Winter 2020: Calculus-based Physics I: Lecture (PH 220-01: MTRF 11:00 to 11:50, 10273) Winter 2020: Thermodynamics and Statistical Physics (PH 360-01: MWF 10:00 to 10:50, 11963) Fall 2019: College Physics I: Lab (PH 201-08: W 11:00 to 13:50, 80956) Winter 2019: Quantum Mechanics: Lecture (PH 410-01: MWF 08:00 to 08:50 , CRN 12047) Fall 2018: College Physics II: Lecture (PH 202-01: MTWR 09:00 to 09:50 , CRN 80392) [All lecture material via WebAssign] Fall 2018: College Physics II: Lab (PH 202 -03: T 18:00 to 20:50 , CRN 80394) Winter 2018: College Physics II: Lecture (PH 202-01: MTWR 09:00 to 09:50 , CRN 10307) [All lecture material via WebAssign] Winter 2018: Thermodynamics and Statistical Physics: Lecture (PH 360-01: MWF 10:00 to 10:50, 12084) Fall 2017: College Physics I: Lecture (PH 201-01: MWRF 14:00 to 14:50 ; CRN 80432) [All lecture material via WebAssign] Fall 2017: College Physics II: Lecture (PH 202-01: MTWR 09:00 to 09:50 ; CRN 80438) [All lecture material via WebAssign] Fall 2017: College Physics II: Lab (PH 202-02: T 10:00 to 12:50 ; CRN 80439) Summer 2017: Directed Study-Condensed Matter Physics Research Winter 2017: College Physics I: Lab (General Info for all lab sections)
[NOTE: Dr. Mengyan's section has more detailed and section specific information available via EduCat] Fall 2016: College Physics 1 Lecture (MWRF 14:00 to 14:50) Fall 2016: College Physics 1 Lab (-03,-04,-08) Courses below here were taught at Texas Tech University Summer 2016: Senior Project (Physics major, PHYS
4306) Winter 2016: Undergraduate Research (Experimental solid-state physics, PHYS 3000) Winter 2016: Principles of Physics I [Calculus-based]
(PHYS 1408-001 CRN: 45473 and 1408-004 CRN: 54556) Winter 2016: Intermediate Physics Lab (PHYS 3304 CRN: 46372) Fall 2015: Undergraduate Research (Experimental solid-state Physics, PHYS 3000) Fall 2015:
Principles of Physics I [Calculus-based] (PHYS 1408-003 CRN: 29508) Summer 2015: Undergraduate Research (Experimental solid-state physics, PHYS 3000) Winter 2015:
General Physics I [Algebra-based] (PHYS 1403-002 CRN: 40292) Winter 2015: Intermediate Physics Lab (PHYS 3304 CRN: 46372) Fall 2014: General Physics I [Algebra-based] (Phys 1403-001) Physics major class flow chart Physics resource guide (As of spring 2021) My field is experimental condensed
matter Physics. I am currently working on a few projects and one
interest resides in the investigation of the microscopic
distribution of magnetic fields within magnetic semiconducting
materials with the prospects of potential applications in spin
electronics. During the course of this particular investigation,
we have found evidence of, what we believe to be, spin polarons
in several types of magnetic materials as well as some
superconducting materials. Some preliminary results seem to
suggest that the spin polaron may be directly related
various exotic magnetic ordering (ie.
helical, etc) or give rise to other
unique properties such as magnetoresistive
behavior, metal to insulator transitions
and, in some cases, superconductivity.
The primary focus of my Ph.D. work
was in dilute magnetic semiconducting systems and their parent
compounds; specifically the investigation of the magnetic
features in Mn doped II-IV-V2 chalcopyrites (such as ZnGeP2:Mn)
as well as the Mn doped II-VI compounds (such as (Cd,Mn)Te).
With a combination of MuSR measurements, neutron scattering and
bulk magnetiztation (SQUID and AGM) measurements, we have determined that spin
polarons likely provide the transfer of magnetism from local moments (Mn) to
the charge carriers (holes) for which neither of the limiting cases for more standard
theories seem to apply. (Link to dissertation:
Magnetism in Mn-Doped Chalcopyrites). Another current project is focused on probing the magnetism, metal to semiconductor transition
and properties of hydrogen in vanadium dioxide (VO2) compounds, via MuSR and neutron scattering.
The focus of this project is to characterize
the local electronic and magnetic environment in a variety of VO2 compounds where the implanted
muon acts as both an experimentally accessible analog to hydrogen and a very sensitive probe of
the local magnetic environment. While still in the early stages, preliminary results show a never before
detected (to our knowledge) low temperature magnetic phase in VO2 compounds (investigated thus far: VO2,
VO2:Ti, VO2:W) where the onset temperature is significantly higher in the doped materials. This project aims
to identify the source of the magnetic phase, characterize the muon/Hydrogen behavior and provide insight
into the highly debated source of the metal to semiconductor transition (including both structural and
electronic components) occurring near room temperature and can be tuned by adjusting the type and concentration
of the dopants. An additional goal is to determine the particular role that the dopants play in modifying these
transitions and related material properties. (Manuscripts are in preparation).
The main research technique that our group utilizes is MuSR, where the 'R' stands for
'Research',
'Rotation', 'Resonance' or 'Relaxation' depending on the
specific application of the technique as being discussed.
Basically, we implant 100% spin polarized muons into a sample and monitor how they interact with the
host system based on the decay signature [e.g see: J.H.
Brewer, et al, "Mu+SR Spectroscopy: The Positive Muon as a
Magnetic Probe in Solids", Physica Scripta 11 (1974) 144-148].
This technique has a wide range of applications beyond being a
very sensitive probe of the magnetic environment, including the
ability to use Muonium (muon that has captured an electron) to
study Hydrogen-like defect centers in semiconducting materials
or a tool to study the Hydrogen atom chemistry in reactions that
would be otherwise unobservable. Additionally, the MuSR
technique can probe the superconducting properties such as the
radii of vortex cores, coherence lengths and penetration depths.
Other applications of the MuSR technique as well as additional
information regarding this experimental method can be found on
http://musr.ca.
Muonium in anatase and brookite TiO2. Muonium as H in Brookite TiO22. A First look at Mu in Anatase TiO2. Role of the Muon in Semiconductor Research. Magnetism and Mu Dynamics in Vanadium Dioxide Compounds. Magnetic Order and Muon Motion in VO2 Compounds
Probing Local Features in Dilute Magnetic Semiconducting ZnGeP2:Mn via Mu+SR Characterization of the Magnetic Phase in Ti-Doped Vanadium Dioxide. Advising
Research Interests
The bulk of my research is carried out at two of the four MuSR
facilities, world-wide; TRIUMF
located in Vancouver, BC and the STFC ISIS facility at Rutherford
Appleton Lab located in Oxfordshire, UK. Independent of my MuSR
work, I have also participated in neutron scattering work at Oak
Ridge National Laboratory (PI: Dr. B.R. Carroll of
Arkansas State University) to further investigate some of the
magnetic properties of the Mn-doped chalcopyrite systems.
Many of the projects in which I am actively involved
are part of collaborations with R.L. Lichti (Texas Tech), R.C. Vilao's group
(University of Coimbra, Portugal), B.B. Baker (Francis Marion University, SC), Y.G. Celebi (Istanbul University, Turkey),
J.H. Brewer (University of British Columbia and TRIUMF, Canada), V.G. Storchak
(Kurchatov Institute, Russia), J.S. Lord (Rutherford Appleton Lab, UK), K. Yokoyama (Rutherford Appleton Lab, UK),
A.J. Drew (Queen Mary University of London, UK) and B.R. Carroll
(Arkansas State University, USA).
Book Chapter:
Selected Publications:
Selected Research Presentations (Primary Author):
(2019: 30th International Conference on Defects in Semiconductors. Seattle, Washington USA)
(2018: Gordon Research Conference on Defects in Semiconductors. New London, NH)
(2017: 14th International Conference on Muon Spin Rotation, Relaxation and Resonance. Sapporo, Japan)
(2017, Invited Talk: March 2017 Meeting of the American Physical Society. New Orleans, LA)
(2014, Talk: TTU Department of Physics Colloquium. Lubbock, TX)
(2014, Poster: Gordon Research Conference: Defects in Semiconductors. Waltham, MA)
(2012, Poster: Gordon Research Conference: Defects in Semiconductors. Biddeford, ME)
Selected Student Research Presentations:
M.R. Goeks, P.W. Mengyan, R.L. Lichti.
(2018: APS Conference for Undergraduate Women in Physics. Toledo, OH)
Characterizating the Muonium Impurity in Anatase TiO2.
J.A. Horn, P.W. Mengyan, R.L. Lichti, J.S. Lord.
(2017: National Ronald E. McNair Research Conference. Schaumburg, IL)
Select Awards
Dec 2019: Excellence in Scholarship Award (Northern Michigan University)
April 2016: Professor of the Year in Physics (Texas Tech University, Physics)
July 2015: Corbett Prize Finalist (28th International Conference on Defects in Semiconductors. Espoo, Finland)
June 2014: Young Scientist Award. (International Society for Muon Spectroscopy, ISMS)
May 2014: Outstanding Ph.D. (TTU Department of Physics).