Sasikanth Manipatruni

Hello! I'm Sasikanth Manipatruni, a scientist and technologist working to build the next generation of computing, using new breakthrough materials applied to AI. My research is focused on the next generation materials and computer architectures to chart a new Moore's Law, driven by quantum materials. I was research director of Intel-FEINMAN center (Functional Electronics Integration and Manufacturing) and senior advisor to the CTO of Intel AI group. Previously I worked at GE-Healthcare demonstrating the first optically readout 3 Tesla MRI. I completed my Ph.D. from Cornell where I worked with Prof. Michal Lipson in ultra-fast silicon electro-optic switches, optomechanical non-reciprocity and synchronization of optomechanical systems. I coach middle/high school students for USA-PHO physics olympiads. As a principle, I do not espouse publicity for scientific/technology work. As Feynman rightly noted, "reality must take precedence over public relations". However, sometimes this does happen especially when there are inflection points for industry. That said, I am happy to chat about technology with just anyone.

Researchmore »

Magneto-Electric Spin-Orbit Logic

Manipatruni, Sasikanth and Nikonov, Dmitri E and Ramesh, Ramamoorthy and Li, Huichu and Young, Ian A

As nanoelectronics approaches the nanometer scale, a massive effort is underway to identify the next scalable logic technology beyond Complementary Metal Oxide Semiconductor (CMOS) transistor based computing. Such computing technology needs to improve switching energy and delay at reduced dimensions, allow improved interconnects and provide a complete logic/memory family. However, a viable beyond-CMOS logic technology has remained elusive. Here, we propose a scalable spintronic logic device which operates via spin-orbit transduction combined with magneto-electric switching. The Magneto-Electric Spin-orbit (MESO) logic enables a new paradigm to continue scaling of logic device performance to near thermodynamic limitsfor GHz logic (100 kT switching energy at 100 ps delay). Read more »

Path to Beyond CMOS with Spin and Polarization

Sasikanth Manipatruni, Dmitri E. Nikonov & Ian A. Young

In this article in Nature Physics, I outlined a path for computing technology that utilizes Spin and Polarization for memory and logic. Abstract : Spintronic and multiferroic systems are leading candidates for achieving attojoule-class logic gates for computing, thereby enabling the continuation of Moore’s law for transistor scaling. However, shifting the materials focus of computing towards oxides and topological materials requires a holistic approach addressing energy, stochasticity and complexity. Read more »

Exchange Bias in Magneto-electric Multi-ferroics

I. A. Young, S. Manipatruni, D. E. Nikonov, C-C Lin, H. Li, R. Ramesh

The physical mechanism for Magneto-electrics at the nano and micro-scale continues to provide new insights. One such key mechanism is the emergence of exchange bias from a partially compensated Anti-Ferro-magnetic (AFM) Multiferroic to a Ferro-magnet. The presence of the AFM order and a canted magnetic moment in this system causes exchange interaction with a ferromagnet such as Co0.9Fe0.1 or La0.7Sr0.3MnO3. Previous research has shown that exchange coupling (uniaxial anisotropy) can be controlled with an electric field. However, voltage modulation of unidirectional anisotropy, which is preferred for logic and memory technologies, has not yet been demonstrated. Here, we present evidence for electric field control of exchange bias of laterally scaled spin valves that is exchange coupled to BFO at room temperature. We show that the exchange bias in this bilayer is robust, electrically controlled, and reversible. Read more »

here's my Phd thesis.

Selected Papers and Postersmore »

(pdf)
Sasikanth Manipatruni, Dmitri E Nikonov, Chia-Ching Lin, Tanay A Gosavi, Huichu Liu, Bhagwati Prasad, Yen-Lin Huang, Everton Bonturim, Ramamoorthy Ramesh, Ian A Young. Scalable energy-efficient magnetoelectric spin–orbit logic. Nature Publishing Group volume 565 Issue 7737, pages 35. January 2019.
Cited by: 105
abstract▾ | bib▾

Since the early 1980s, most electronics have relied on the use of complementary metal–oxide–semiconductor (CMOS) transistors. However, the principles of CMOS operation, involving a switchable semiconductor conductance controlled by an insulating gate, have remained largely unchanged, even as transistors are miniaturized to sizes of 10 nanometres. We investigated what dimensionally scalable logic technology beyond CMOS could provide improvements in efficiency and performance for von Neumann architectures and enable growth in emerging computing such as artifical intelligence. Such a computing technology needs to allow progressive miniaturization, reduce switching energy, improve device interconnection and provide a complete logic and memory family. Here we propose a scalable spintronic logic device that operates via spin–orbit transduction (the coupling of an electron’s angular momentum with its linear momentum) combined with magnetoelectric switching. The device uses advanced quantum materials, especially correlated oxides and topological states of matter, for collective switching and detection. We describe progress in magnetoelectric switching and spin–orbit detection of state, and show that in comparison with CMOS technology our device has superior switching energy (by a factor of 10 to 30), lower switching voltage (by a factor of 5) and enhanced logic density (by a factor of 5). In addition, its non-volatility enables ultralow standby power, which is critical to modern computing. The properties of our device indicate that the proposed technology could enable the development of multi-generational computing.
```
      @article{manipatruni2019scalable,
        title={Scalable energy-efficient magnetoelectric spin--orbit logic},
        author={Manipatruni, Sasikanth and Nikonov, Dmitri E and Lin, Chia-Ching and Gosavi, Tanay A and Liu, Huichu and Prasad, Bhagwati and Huang, Yen-Lin and Bonturim, Everton and Ramesh, Ramamoorthy and Young, Ian A},
        journal={Nature},
        volume={565},
        number={7737},
        pages={35},
        year={2019},
        publisher={Nature Publishing Group}
      }
    
```
(pdf)
Sasikanth Manipatruni, Dmitri E. Nikonov, Ian A. Young. Modeling and Design of Spintronic Integrated Circuits. IEEE Transactions on Circuits and Systems I: Regular Papers, volume 59,issue 12, pages 2801-2814. 21 November 2012.
Cited by: 76
abstract▾ | bib▾

We present a theoretical and a numerical formalism for analysis and design of spintronic integrated circuits (SPINICs). The formalism encompasses a generalized circuit theory for spintronic integrated circuits based on nanomagnetic dynamics and spin transport. We propose an extension to the modified nodal analysis technique for the analysis of spin circuits based on the recently developed spin conduction matrices. We demonstrate the applicability of the framework using an example spin logic circuit described using spin Netlists.
```
        @article{manipatruni2012modeling,
          title={Modeling and design of spintronic integrated circuits},
          author={Manipatruni, Sasikanth and Nikonov, Dmitri E and Young, Ian A},
          journal={IEEE Transactions on Circuits and Systems I: Regular Papers},
          volume={59},
          number={12},
          pages={2801--2814},
          year={2012},
          publisher={IEEE}
        }
      
```
(pdf)
Sasikanth Manipatruni, Qianfan Xu, Bradley Schmidt, Jagat Shakya, Michal Lipson. High speed carrier injection 18 Gb/s silicon micro-ring electro-optic modulator. LEOS 2007-IEEE Lasers and Electro-Optics Society Annual Meeting Conference Proceedings, pages 537-538. 21 October 2007.
Cited by: 1101
abstract▾ | bib▾

We experimentally demonstrate electrooptic modulation in silicon at 18 Gbps (NRZ) in a micro-ring of 12 micron diameter using a pre-emphasis technique. Device simulations indicate that this technique can extend the bit rate to 40 Gbps.
```
  @inproceedings{manipatruni2007high,
    title={High speed carrier injection 18 Gb/s silicon micro-ring electro-optic modulator},
    author={Manipatruni, Sasikanth and Xu, Qianfan and Schmidt, Bradley and Shakya, Jagat and Lipson, Michal},
    booktitle={LEOS 2007-IEEE Lasers and Electro-Optics Society Annual Meeting Conference Proceedings},
    pages={537--538},
    year={2007},
    organization={IEEE}
  }
```
(pdf)
Sasikanth Manipatruni, Jacob T Robinson, Michal Lipson. Optical non-reciprocity in optomechanical structures. Phys. Rev. Lett volume 102 Issue 21, pages 213903. 31 May 2009.
Cited by: 150
abstract▾ | bib▾

We demonstrate that optomechanical devices can exhibit nonreciprocal behavior when the dominant light-matter interaction takes place via a linear momentum exchange between light and the mechanical structure. As an example, we propose a microscale optomechanical device that can exhibit a nonreciprocal behavior in a microphotonic platform operating at room temperature. We show that, depending on the direction of the incident light, the device switches between a high and low transparency state with more than a 20 dB extinction ratio.
```
      @article{manipatruni2009optical,
        title={Optical nonreciprocity in optomechanical structures},
        author={Manipatruni, Sasikanth and Robinson, Jacob T and Lipson, Michal},
        journal={Physical review letters},
        volume={102},
        number={21},
        pages={213903},
        year={2009},
        publisher={APS}
      }
    
```
(pdf)
Manipatruni, Sasikanth and Nikonov, Dmitri E and Liu, Huichu and Young, Ian A. Response to Comment on'Spin-Orbit Logic with Magnetoelectric Nodes: A Scalable Charge Mediated Nonvolatile Spintronic Logic. arXiv preprint arXiv:1703.01559. 5 March 2017.

abstract▾ | bib▾

In this technical note, we address the comments on the energy estimates for Magnetoelectric Spin-orbit (MESO) Logic, a new logic device proposed by the authors. We provide an analytical derivation of the switching energy, and support it with time-domain circuit simulations using a self-consistent ferroelectric (FE) compact model. While the energy to charge a capacitor is dissipated in the interconnect and transistor resistance, we note that the energy to switch a capacitor and a FE is independent of the interconnect resistance value to the first order. Also device design can mitigate the parasitic energy losses. We further show the circuit simulations for a sub 10 aJ switching operation of a MESO logic device comprehending: a) Energy stored in multiferroic; b) Energy dissipation in the resistance of the interconnect, Ric ; c) Energy dissipation in the inverse spin-orbit coupling (ISOC) spin to charge converter Risoc; d) Supply, ground resistance, and transistor losses. We also identify the requirements for the resistivity of the spin-orbit coupling materials and address the effect of internal resistance of the spin to charge conversion layer. We provide the material parameter space where MESO (with a fan-out of 1 and interconnect) achieves sub 10 aJ switching energy with path for scaling via ferroelectric/magnetoelectric/spin-orbit materials development.
```
    @article{manipatruni2017response,
      title={Response to Comment on'Spin-Orbit Logic with Magnetoelectric Nodes: A Scalable Charge Mediated Nonvolatile Spintronic Logic'(arXiv: 1607.06690)},
      author={Manipatruni, Sasikanth and Nikonov, Dmitri E and Liu, Huichu and Young, Ian A},
      journal={arXiv preprint arXiv:1703.01559},
      year={2017}
    }
  
```
(pdf)
Manipatruni, Sasikanth and Nikonov, Dmitri and Young, Ian A. Vector spin modeling for magnetic tunnel junctions with voltage dependent effects. Journal of Applied Physics, volume 115, issue 17, pages 17B754. 7 May 2014.
Cited by: 11
abstract▾ | bib▾

Integration and co-design of CMOS and spin transfer devices requires accurate vector spin conduction modeling of magnetic tunnel junction (MTJ) devices. A physically realistic model of the MTJ should comprehend the spin torque dynamics of nanomagnet interacting with an injected vector spin current and the voltage dependent spin torque. Vector spin modeling allows for calculation of 3 component spin currents and potentials along with the charge currents/potentials in non-collinear magnetic systems. Here, we show 4-component vector spin conduction modeling of magnetic tunnel junction devices coupled with spin transfer torque in the nanomagnet. Nanomagnet dynamics, voltage dependent spin transport, and thermal noise are comprehended in a self-consistent fashion. We show comparison of the model with experimental magnetoresistance (MR) of MTJs and voltage degradation of MR with voltage. Proposed model enables MTJ circuit design that comprehends voltage dependent spin torque effects, switching error rates, spin degradation, and back hopping effects.
```
      @article{manipatruni2014vector,
        title={Vector spin modeling for magnetic tunnel junctions with voltage dependent effects},
        author={Manipatruni, Sasikanth and Nikonov, Dmitri E and Young, Ian A},
        journal={Journal of Applied Physics},
        volume={115},
        number={17},
        pages={17B754},
        year={2014},
        publisher={AIP}
      }
    
```
(pdf)
Mian Zhang,Gustavo S. Wiederhecker,Sasikanth Manipatruni,Arthur Barnard,Paul McEuen,and Michal Lipson. Synchronization of Micromechanical Oscillators Using Light. Physics review letters, volume 109, issue 23, pages 233906. 5 December 2012.
Cited by: 288
abstract▾ | bib▾

Synchronization, the emergence of spontaneous order in coupled systems, is of fundamental importance in both physical and biological systems. We demonstrate the synchronization of two dissimilar silicon nitride micromechanical oscillators, that are spaced apart by a few hundred nanometers and are coupled through an optical cavity radiation field. The tunability of the optical coupling between the oscillators enables one to externally control the dynamics and switch between coupled and individual oscillation states. These results pave a path toward reconfigurable synchronized oscillator networks.
```
        @article{zhang2012synchronization,
          title={Synchronization of micromechanical oscillators using light},
          author={Zhang, Mian and Wiederhecker, Gustavo S and Manipatruni, Sasikanth and Barnard, Arthur and McEuen, Paul and Lipson, Michal},
          journal={Physical review letters},
          volume={109},
          number={23},
          pages={233906},
          year={2012},
          publisher={APS}
        }
      
```

Google scholar | see all papers and posters »

Selected Patents

Spin-orbit logic with charge interconnects and magnetoelectric nodes. Sasikanth Manipatruni, Dmitri E. Nikonov, Ian A. Young
United States Patent, Patent No. US 10,062,731 B2 , Date Aug. 28, 2018
Electro-optical modulator. Sasikanth Manipatruni, Qianfan Xu, Michal Lipson
United States Patent, Patent No. US 8,295,655 B2 , Date Oct. 23, 2012
MTJ spin hall MRAM bit-cell and array. Sasikanth Manipatruni, Dmitri E. Nikonov, Ian A. Young
United States Patent, Patent No. US 9,620,188 B2 , Apr. 11, 2017
Photonic system and method for optical data transmission in medical imaging systems Christopher Judson Hardy, Sasikanth Manipatruni
United States Patent, Patent No. US 8,847,598 B2 , Sep. 30, 2014
Low synch dedicated accelerator with in-memory computation capability Amrita MATHURIYA, Sasikanth Manipatruni, Victor Lee, Huseyin SUMBUL, Gregory Chen, Raghavan Kumar, Phil Knag, Ram Krishnamurthy, Ian Young, Abhishek Sharma
United States Patent, Patent No. US 2019/0056885 A1 , Feb. 21 , 2019
Three-dimensional quaternary and six state magnetic circuits Sasikanth Manipatruni, Patrick Morrow, Dmitri E. Nikonov, Chia-Ching Lin, Uygar E. Avci, Ian A. Young
Patent No. WO 2018/125107 Al