# N. Peter Armitage

## Associate Professor

Bloomberg 309

410-516-0621

npa@jhu.edu

Curriculum Vitae

Group/Lab Website

Google Scholar Profile

N. Peter Armitage has been on the faculty of the Department of Physics and Astronomy at Johns Hopkins University since 2006. He is a physicist whose research centers on exotic electronic states of matter at low temperatures, including novel superconductors, exotic magnetic states, electronic glasses, topological insulators, strong spin-orbit coupling, and materials in proximity to quantum critical points. Like waves on the sea, the behavior of such systems is intrinsically collective and is not easily reduced to the properties of individual particles – i.e., they are emergent. Dr. Armitage's principal scientific interest is understanding how is it that large ensembles of strongly interacting, but fundamentally simple particles like electrons in solids act collectively to exhibit complex emergent quantum phenomena. He is exploiting (and developing) recent technical breakthroughs using very low frequency microwave and THz range radiation to probe these systems at their natural frequency scales. The material systems of interest require new measurement techniques as their relevant frequencies typically fall between the range of usual optical and electronic methods. He has been the recipient of a DARPA Young Faculty Award, an NSF Career Award, a Sloan Research Fellowship, was a three time Kavli Frontiers Fellow, the winner of the first William Spicer Award from SSRL in 2004, and was the winner of the 2005 William L. McMillan Award from the University of Illinois for "outstanding contributions in condensed matter physics."

- Advance Condensed Matter Physics - Spring 2012
- Classical Mechanics 105 - Fall 2011
- Introduction to Condensed Matter Physics - Fall 2010
- Introduction to Condensed Matter Physics - Fall 2009
- Introduction to Condensed Matter Physics - Fall 2008
- The Advanced and Intermediate Lab - Spring 2008

Please also check out my perpetually updated lecture notes on "Electrodynamics of correlated electron systems".

These are based on lectures I first gave at the "2008 Boulder School for Condensed Matter and Materials Physics."

See the videos of these lectures here: Formalism and Techniques and Examples and Advanced Analysis

Displaying the 20 most recent publications. View the Google Scholar Profile for complete publications list.

Note: Please refresh the page if no publications initially appear.

D Chaudhuri, B Cheng, A Yaresko, QD Gibson, RJ Cava, NP Armitage

An optical investigation of the strong spin-orbital coupled magnetic semimetal YbMnBi $ _2$

**arXiv preprint arXiv:1701.08693, 2017 **

L Wu, M Salehi, N Koirala, J Moon, S Oh, NP Armitage

Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator

**Science 354 (6316), 1124-1127, 2016 **

B Cheng, L Wu, SK Kushwaha, RJ Cava, NP Armitage

Measurement of the topological surface state optical conductance in bulk-insulating Sn-doped Bi 1.1 Sb 0.9 Te 2 S single crystals

**Physical Review B 94 (20), 201117, 2016 **

L Zhao, CA Belvin, R Liang, DA Bonn, WN Hardy, NP Armitage, D Hsieh

A global inversion-symmetry-broken phase inside the pseudogap region of YBa2Cu3Oy

**Nature Physics, 2016 **

NJ Laurita, CM Morris, SM Koohpayeh, PFS Rosa, WA Phelan, Z Fisk, ...

Anomalous three-dimensional bulk ac conduction within the Kondo gap of SmB 6 single crystals

**Physical Review B 94 (16), 165154, 2016 **

M Brahlek, N Koirala, M Salehi, J Moon, W Zhang, H Li, X Zhou, MG Han, ...

Disorder-driven topological phase transition in B i 2 S e 3 films

**Physical Review B 94 (16), 165104, 2016 **

A Akrap, M Hakl, S Tchoumakov, I Crassee, J Kuba, MO Goerbig, ...

Magneto-Optical Signature of Massless Kane Electrons in Cd 3 As 2

**Physical Review Letters 117 (13), 136401, 2016 **

NJ Laurita, B Cheng, R Barkhouser, VA Neumann, NP Armitage

A Modified 8f Geometry with Reduced Optical Aberrations for Improved Time Domain Terahertz Spectroscopy

**Journal of Infrared, Millimeter, and Terahertz Waves 37 (9), 894-902, 2016 **

NP Armitage

Quantum materials: Kitaev's exact solution approximated

**Nature Materials 15 (7), 701-702, 2016 **

L Wu, RM Ireland, M Salehi, B Cheng, N Koirala, S Oh, HE Katz, ...

Tuning and stabilizing topological insulator Bi2Se3 in the intrinsic regime by charge extraction with organic overlayers

**Applied Physics Letters 108 (22), 221603, 2016 **

B Cheng, L Wu, NJ Laurita, H Singh, M Chand, P Raychaudhuri, ...

Anomalous gap-edge dissipation in disordered superconductors on the brink of localization

**Physical Review B 93 (18), 180511, 2016 **

M Neshat, NP Armitage, , NP Armitage

Terahertz time-domain spectroscopic ellipsometry system

**US Patent 9,322,712, 2016 **

L Wu, M Salehi, N Koirala, J Moon, S Oh, NP Armitage

Quantized Faraday and Kerr rotation and axion electrodynamics of the surface states of three-dimensional topological insulators

**arXiv preprint arXiv:1603.04317, 2016 **

G Bossé, LD Pan, YS Li, LH Greene, J Eckstein, NP Armitage

Anomalous frequency and temperature-dependent scattering and Hund's coupling in the almost quantum critical heavy-fermion system CeFe 2 Ge 2

**Physical Review B 93 (8), 085104, 2016 **

LD Pan, NJ Laurita, KA Ross, BD Gaulin, NP Armitage

A measure of monopole inertia in the quantum spin ice Yb2Ti2O7

**Nature Physics, 2015 **

N Koirala, M Brahlek, M Salehi, L Wu, J Dai, J Waugh, T Nummy, MG Han, ...

Record surface state mobility and quantum Hall effect in topological insulator thin films via interface engineering

**Nano Letters 15 (12), 8245-8249, 2015 **

L Wu, WK Tse, M Brahlek, CM Morris, RV Aguilar, N Koirala, S Oh, ...

High-resolution Faraday rotation and electron-phonon coupling in surface states of the bulk-insulating topological insulator Cu 0.02 Bi 2 Se 3

**Physical review letters 115 (21), 217602, 2015 **

M Salehi, M Brahlek, N Koirala, J Moon, L Wu, NP Armitage, S Oh

Stability of low-carrier-density topological-insulator Bi2Se3 thin films and effect of capping layers

**APL Materials 3 (9), 091101, 2015 **

VA Neumann, NJ Laurita, LD Pan, NP Armitage

Reduction of effective terahertz focal spot size by means of nested concentric parabolic reflectors

**AIP advances 5 (9), 097203, 2015 **

NJ Laurita, J Deisenhofer, LD Pan, CM Morris, M Schmidt, M Johnsson, ...

Publisher’s Note: Singlet-Triplet Excitations and Long-Range Entanglement in the Spin-Orbital Liquid Candidate FeSc 2 S 4 [Phys. Rev. Lett. 114, 207201 (2015)]

**Physical Review Letters 115 (1), 019901, 2015 **