Report  on  the  6th  Conference  of  the  Asian  Consortium  on  Computational  Materials  Science  (ACCMS-­‐6)  6-­‐7  September  2011,  Biopolis,  Singapore    The   6th   Conference   of   the   Asian   Consortium   on   Computational  Materials   Science   (ACCMS-­‐6)  was  held  in  Singapore  during  6  -­‐  9  September  2011.  The  conference  was  jointly  organized  by  the  National  University   of   Singapore   (NUS),  Materials   Research   Society   of   Singapore   (MRS-­‐S),   Institute   of   High  Performance   Computing   (IHPC),   and   Institute   of   Advanced   Studies   (IAS)   at   the   Nanyang  Technological  University,  with  financial  supports  from  NUS,  MRS-­‐S,  IHPC,  IAS,  Lee  Foundation,  US  Air  Force  Office  of  Scientific  Research  Asian  Office  of  Aerospace  R  &  D,  Novaglobal  Pte  Ltd,  Accelrys,  and  Singapore  Tourism  Board.    The   ACCMS   was   established   to   nurture   and   promote   research   and   development   activities   in  computational  materials  science  in  Asian  countries.  The  biennial  ACCMS  conference  has  become  an  international   event   for   exchanging   information   and   sharing   latest   developments   in   advanced  computational   methodologies   and   their   applications   in   material   science   and   engineering.   The  previous   ACCMS   conferences  were   successful   held   in   India   (Bangalore   2001),   Russia   (Novosibirsk,  2004),   China   (Beijing,   2005),   Korea   (Seoul,   2007),   and   Vietnam   (Hanoi,   2009).   ACCMS-­‐6   drew   180  participants  from  19  countries/regions.  Countries/regions  strong  in  computational  materials  science  such  as  Japan,  Korea,  China,  India,  Singapore,  and  Taiwan  were  well  represented.  ACCMS-­‐6  also  saw  a  significantly  increased  number  of  participants  from  countries  such  as  Thailand  (14)  and  Vietnam  (7)  that  are  fast  developing  research  activities  in  computational  materials  science.        

 Participants  of  ACCMS-­‐6    

The  conference  covered  topics  ranging  from  fundamental  computational  methodologies  (density  functional  theory  and  beyond,  quantum  mechanical  based  interatomic  potentials,  molecular  dynamic  and  Monte-­‐Carlo  simulation  of  thermodynamic  and  kinetic  properties  at  large  length  and  time  scales,  phase  field  method  of  micro-­‐structural  simulation,  etc.)  to  their  applications  in  understanding  different  materials  properties  as  well  as  predicting  new  ones.    Highlights  of  the  Conference    The  three-­‐day  conference  consisted  of  plenary  sessions,   invited  talks,  contributed  talks,  and  poster  presentations,   covering   a   wide   range   of   topics   of   computational   materials   science.  Many   leading  computational   materials   scientists   in   Asia,   such   as   Professor   Jisoon   Ihm   from   Korea,   Professor  Yoshiyuki   Kawazoe   from   Japan,   Professors   Enge   Wang   and   Xingao   Gong   from   mainland   China,  Professor  C  T  Chan  from  Hong  Kong,  Professor  Mei-­‐Yin  Chou  from  Taiwan,  Professors  G  P  Das  and  Vijay   Kumar   from   India,   to   name   only   a   few,   attended   the   conference   and   presented   their   latest  research  findings.  Top  researchers  from  other  parts  of  the  world  such  as  Professors  Steven  G.  Louie  

and  P.   Juna   from  US,  Professor  O.  K.  Andersen   from  Germany,  Professor   J.   Tse   from  Canada  were  invited  to  give  talks  at  the  conference.      Two  plenary   lectures  were  delivered  by  Professor  Steven  G.  Louie  of  the  University  of  California  at  Berkeley  and  Professor  O.  K.  Andersen  of  the  Max  Plank  Institute  for  Solid  State  Research,  Stuttgart,  respectively.   In   his   plenary   lecture,   Professor   Louie   presented   recent   progress   in   employing   and  extending   the   GW   approach   to   novel  materials,   defects   in   solids,   nanostructures,   and  molecules.  Results   from   some   selected   systems   and   several   conceptual   and   methodological   issues   were  discussed.   It   is   noted   that   with   the   recent   advances,   ab   initio   GW   calculations   of   systems   with  hundreds  of  atoms  may  now  be  done.  As  illustrations,  Professor  Louie  described  findings  on  several  systems   of   current   interest,   including   investigations   on   the   properties   of   graphene   and   graphene  nanostructures,   charge   transition   levels   and   spectroscopic   properties   of   defects   in   solids   (e.g.,  vacancies   in   hafnia   and   the   NV-­‐   center   in   diamond),   electronic   multiplet   structure   in   open-­‐shell  systems,   and   topologically   protected   surface   states   on   topological   insulators.   In   the  other   plenary  lecture,   Professor   O.   K.   Andersen   illustrated   how   electronic   structure   calculations   can   be   used   to  design  superconductors  with  higher  Tc,  based  on  nickelates,  instead  of  cuprates.      

   Professor  O.  K.  Andersen  (left)  and  Professor  S.  G.  Louie  delivering  their  plenary  lectures.    

 A   number   of   speakers   presented   latest   developments   in   computational   methods,   including   GW  approximation,   quantum   Monte   Carlo,   all-­‐electron   mixed-­‐basis   ab   initio   method,   multiscale  simulation,   molecular   dynamics   based   on   self-­‐consistent   and   environment   dependent   (SCED)  Hamiltonian  developed  in  the  framework  of  linear  combination  of  atomic  orbitals  (LCAO),  magnetic  potentials  coarse-­‐grained  from  electronic  structure  calculations  for  defect  modeling,  etc.      As   in   other   materials   science   conferences   in   recent   years,   graphene,   topological   insulators   and  related   materials   were   favorite   topics   and   prominently   featured   in   ACCMS-­‐6.   A   number   of  presentations   were   devoted   to   computational   studies   of   bilayer   graphene,   twisted   multilayer  graphene,   hydrogenated   graphene,   graphene   superlattices   and   nanoribbons,   graphene   oxide,   as  well   as   related   materials   such   as   boron   nitride   sheet.   Another   type   of   materials   that   strongly  featured   in   ACCMS-­‐6   presentations   were   energy   storage   materials,   such   as   hydrogen   storage  materials,  solid  state  batteries,  and  photovoltaic  materials.      Computational   approaches,   particularly   based   on   ab   initio   electronic   structure   methods,   have  become   important   tools   in   discovering   and   designing   new  materials.  Materials   design   was   also   a  popular  topic  among  papers  presented  at  ACCMS-­‐6.  Y  H  Lu  of  NUS  proposed  a  new  hexagonal  phase  for  TiO2  which  has  a  smaller  band  gap  and  can  make  more  efficient  use  of  sun  light  in  photocatalytic  hydrogen  production.  P.  Sen  of  Harish-­‐Chandra  Research  Institute  presented  his  work  on  design  of  a  new  class  of  magnetic  superatoms.      

In  addition  to  high  quality  invited  and  contributed  oral  presentations,  more  than  half  of  the  papers  were  presented  as  posters,  which  allowed  more  interactions  between  the  authors  and  participants  of  the  conference.  Five  posters  were  chosen  from  the  84  posters  presented  for  the  Kawazoe  poster  awards.  The  authors  were  presented  with  a  certificate,  a  book  (co)-­‐authored  by  Y.  Kawazoe  and  cash  prizes  during  the  conference  banquet  held  on  8  September  2011.    

List  of  Kawazoe  Poster  Award  winners    ACCMS  Short  Courses    Following  the  tradition  of  previous  ACCMS  conferences,  two  one-­‐day  pre-­‐conference  short  courses  were   organized   on   6   September   2011.   These   short   courses   were   designed   to   provide   a   practical  starting  point  of  materials  research  using  computational  methods.  The  two  short  courses  of  ACCMS-­‐6   were   designed   to   address   two   challenging   issues   in   computational   materials   science,   i.e.,  simulating  large  systems  such  as  nanostructures  and  achieving  high  accuracy.      The  short  course  programme  started  with  an  introductory  lecture  by  Professor  G  P  Das  of  the  Indian  Association   for   the   Cultivation   of   Science.   Professor   Das   presented   an   overview   of   the   density  functional  theory  and  the  different  basis  sets  used  viz.  plane  wave,  spherical  waves,  atomic  orbitals,  muffin-­‐tin  orbitals,  and  mixed  basis  sets,  leading  to  various  state-­‐of-­‐the-­‐art  DFT  based  packages.  This  set   the  stage   for   the  two  short  courses  “Quantum  Mechanics  based  Simulations  of  Real  Materials:  SCED-­‐LCAO”  and  “Tohoku  Mixed  Basis  Orbitals  ab  initio  Program  (TOMBO)”.      In   the   SCED-­‐LCAO   short   course,   Professors   C.   S.   Jayanthi   and  M.   Yu   of   the  University   of   Louisville  introduced   the   self-­‐consistent   and   environment   dependent   (SCED)   Hamiltonian   developed   in   the  framework  of  linear  combination  of  atomic  orbitals  (LCAO).  This  semiempirical  method  includes  two-­‐center  as  well  as  multi-­‐center  electron-­‐ion  interactions,  on-­‐site  electron-­‐electron  correlations  as  well  as   inter-­‐site  electron-­‐electron  correlations.   It   is  designed  to  address  the  size  bottleneck  of  ab  initio  simulations   as   well   as   the   issue   of   non-­‐transferability   of   most   of   the   existing   semi-­‐empirical  Hamiltonians.   Benchmarking   calculations   show   that   the   SCED-­‐LCAO-­‐MD   scheme   is   about   30   times  faster  than  DFT-­‐based  VASP  software  and   it  requires  about  five  times   less  memory.   In  addition,  by  implementing   the   order-­‐N   scheme   into   the   framework   of   the   SCED-­‐LCAO   Hamiltonian   for   total  energy  and  force  calculations,  full  geometry  optimization  can  be  performed  for  systems  of  sizes  up  to   20,000   atoms.   Thus   reliable   large-­‐scale   quantum-­‐mechanics   based   MD   simulations   are   now  attainable   using   the   O(N)/SCED-­‐LCAO   scheme.   Participants   of   the   short   course   had   chances   to  experience   the   robustness  of   the  SCED-­‐LCAO  Hamiltonian   through  selected  case   studies  of   carbon  that  included  the  C29  cluster,  the  bucky-­‐diamond  carbon,  the  (5,0)  single  wall  carbon  nanotube,  and  graphene.      

Authors   Organization   Topic  

Chan-­‐Yeup  Chung,  Hiroshi  Mizuseki,  and  Yoshiyuki  Kawazoe  

Institute  for  Materials  Research,  Tohoku  University,  Japan  

Oxygen  Vacancy  Effects  on  Single  Crystalline  La3Ta0.5Ga5.5O11  Piezoelectric  Materials  

Do  Ngoc  Son  and  Takahashi  Kaito   Academia  Sinica,  Taiwan   Selectivity  of  PdCo  Alloy  towards  Oxygen  Reduction  Reaction  

Jeongwoon  Hwang,  Changwon  Park,  Gunn  Kim,  and  Jisoon  Ihm    

Seoul  National  University   Pseudospin  Rotation  and  Valley  Mixing  in  Electron  Scattering  at  Various  Graphene  Edges    

Ming  Yang,  Chun  Zhang,  Yuanping  Feng,  and  Ariando  

National  University  of  Singapore   Ultra-­‐Flat  Graphene  on  Si3N4  with  High  Electron  Mobility  

Xiaoping  YANG  and  Haibin  SU   Nanyang  Technological  University,  Singapore  

Polarization  and  Electric  Field  Dependence  of  Electronic  Properties  in  LaAlO3/SrTiO3  heterostructures  

In   the   TOMBO   short   course,   Professor   Kawazoe   and   his   team   from   the   Institute   of   Materials  Research,   Tohoku   University,   introduced   the   Tohoku   Mixed   Basis   Orbitals   ab   initio   program  (TOMBO).   Kawazoe   Laboratory   has   been   developing   this   first-­‐principles   simulation   package   in   the  last  15  years.  It  is  based  on  the  all-­‐electron  mixed  basis  approach  in  which  electron  wave  functions  are  expressed  by  using  both  plane  waves  (PWs)  and  atomic  orbitals  (AOs).  Since  AOs  are  numerically  defined   inside   the   non-­‐overlapping   atomic   spheres   in   radial   (logarithmic)   mesh,   all-­‐electron  calculations   with   PWs   can   be   performed   very   accurately   with   a   modest   computational   cost.   The  number   of   PWs   required   in   this   method   is   significantly   fewer   than   that   required   in   standard  pseudopotential   or   PAW   methods.   Moreover,   one   can   avoid   problems   such   as   the   basis   set  superposition   error   (BSSE)   appearing   in   standard   LCAO   methods   and   the   over-­‐completeness  problem  appearing  in  standard  mixed-­‐basis  methods.  TOMBO  can  describe  extended  PW-­‐like  states  as  well  as  well  localized  core  states  with  modest  number  of  basis  functions.  It  is  applicable  to  various  kinds   of   systems   including   atoms,  molecules,   clusters,   surfaces,   and   crystals.   Therefore,   it   has   an  apparent   advantage   compared   to  many   preexisting   first-­‐principles  methods.   During   the   hands-­‐on  sessions,   participants  of   the   short   courses  had   first-­‐hand  experience   in   the   study  of   CH4  molecule  and   hydrogen   storage   materials   such   as   metal   organic   frameworks   (MOFs).   Another   interesting  application  of  TOMBO   is   to   simulate  electron  dynamics  of  an  electronic  excited   state   in  materials.  The  time  evolution  of  the  electrons  and  holes  in  the  electronic  excited  states  can  be  treated  by  using  TOMBO   on   the   basis   of   the   adiabatic   local   density   approximation   (adiabatic   LDA)   in   the   time-­‐dependent   density   functional   theory   (TDDFT)   combined   with   the   Ehrenfest   theorem   for   the  adiabatic  process.  As  a  very  simple  example,   the  possibility  of  dissociation  of  a  hydrogen  molecule  around  a  nickel  dimer  was  studied.      

 Participants  of  ACCMS-­‐6  Workshops.    

ACCMS  Award    Another   highlight   of   ACCMS-­‐6  was   the   presentation   of   the   2011  ACCMS   award   to   Professor   Enge  Wang,  School  of  Physics,  Peking  University,  China,  at  the  conference  banquet  held  in  the  evening  of  8   September.   The   ACCMS   Award   is   to   recognize   scientists   in   Asia   who   have   made   outstanding  contributions   to   computational  materials   science   and   to  ACCMS.   Since   2004,   the  Award  has   been  

presented  at  ACCMS  general  meeting.  Prof.  Wang  was  recognized  for  his  outstanding  contributions  to  atomistic   simulations  of   surface  growth  dynamics  and   the   formation  of  nanostructures,  and  his  support  to  ACCMS.    Enge  Wang  received  his  Bachelor  degree  in  theoretical  physics  from  Liaoning  University  (1982)  and  obtained   his   Ph.D.   in   condensed   matter   physics   from   Peking   University   (1990).   After   spending  several   years   at   Princeton   University,   Institut   d’Electronique,   de   Microelectronique   de  Nanotechnologie   (France),  and  University  of  Houston,  he   started  his  academic  career   in  1995  as  a  professor  at  the  Institute  of  Physics,  Chinese  Academy  of  Sciences  (CAS).  He  was  the  Director  of  the  Institute  of  Physics  (CAS)  from  1999  to  2007.  Currently,  he  is  a  Vice  President  and  Provost  at  Peking  University.   Enge   is   the   recipient   of   many   prestigious   awards   including   the   HLHL   Science   and  Technology  Award  (2010),  the  Humboldt  Research  Award  (2005),  the  TWAS  Award  in  Physics  (2005),  the  IBM  Faculty  Award  (2003–2004),  the  Achievement  in  Asia  Award  (AAA)  of  the  Overseas  Chinese  Physics  Association  (2002–2003),  and  “Zhou  Pei-­‐Yuan  Physics  Awards”  (CPS,  2005).  He  was  elected  an  Academician  of   the  Chinese  Academy  of  Sciences   in  2007  and  the  Academy  of  Sciences   for   the  Developing  World  (TWAS)  in  2008,  and  a  Fellow  of  the  American  Physical  Society  in  2006.  Enge  was  the  Chair  of  the  third  ACCMS  general  meeting  which  was  held  in  Beijing  in  2005.    In  his  award  lecture  in  the  morning  of  9  September,  Prof.  Wang  presented  his  latest  work  on  surface  of   ice.     Using   computer   simulation,   Prof.   Wang   and   his   team   discovered   unusual   structure   and  dynamics  of  ice  surface  at  atomic  scale.  An  order  parameter  which  defines  the  surface  energy  of  ice  Ih  surfaces  has  been  identified  for  the  first  time.  They  also  predicted  that  the  proton  order-­‐disorder  transition,  which  occurs  in  the  bulk  at  ∼72  K,  will  not  occur  at  the  surface  at  any  temperature  below  surface  melting.   In   addition,   they   found   that   vacancy   formation   on   crystalline   ice   surface   exhibits  characteristics   of   an   amorphous   material,   and   the   formation   of   vacancies   facilitates   pits   on   the  surface  and  other  processes  that  may  contribute  to  pre-­‐melting  and  formation  of  a  quasi-­‐liquid  layer.  Despite  ice  being  a  ubiquitous  and  well-­‐studied  substance,  Prof.  Wang’s  work  provides  new  insights  to  basic  surface  properties  and  structure  of  ice.    

 Professor  Kawazoe  is  presenting  the  ACCMS  Award  to  Professor  Enge  Wang  at  the  ACCMS-­‐6  banquet    on  8  September  2011,  with  Professor  G  P  Das,  citation  reader  (left),  and  Professor  Yuan  Ping  Feng,    Co-­‐chair  of  ACCMS-­‐6  (right),  looking  on.    

ACCMS-­‐7    At  the  International  Advisory  Committee  meeting  held  on  8  September,  it  was  decided  that  the  next  ACCMS  conference,  ACCMS-­‐7,  will  be  held   in  Thailand.  Professor  Sukit  Limpijumnong  of  Suranaree  University  of  Technology  will  lead  the  organizing  committee.  Details  of  ACCMS-­‐7  will  be  announced  later.      

 Professor  Sukit  Limpijumnong,  Chair  of  ACCMS-­‐7,  inviting  participants  to  Thailand  in  2013.      ACCMS-­‐6  web  site    More  information  about  ACCMS-­‐6  can  be  found  at  the  conference  web  site:  http://www.mrs.org.sg/accms6/